The interest earned on a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis are all intimately connected with the mysterious number e. In this informal and engaging history, Eli Maor portrays the curious characters and the elegant mathematics that lie behind the number. Designed for a reader with only a modest mathematical The interest earned on a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis are all intimately connected with the mysterious number e. In this informal and engaging history, Eli Maor portrays the curious characters and the elegant mathematics that lie behind the number. Designed for a reader with only a modest mathematical background, this biography brings out the central importance of e to mathematics and illuminates a golden era in the age of science.

# e: the Story of a Number

The interest earned on a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis are all intimately connected with the mysterious number e. In this informal and engaging history, Eli Maor portrays the curious characters and the elegant mathematics that lie behind the number. Designed for a reader with only a modest mathematical The interest earned on a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis are all intimately connected with the mysterious number e. In this informal and engaging history, Eli Maor portrays the curious characters and the elegant mathematics that lie behind the number. Designed for a reader with only a modest mathematical background, this biography brings out the central importance of e to mathematics and illuminates a golden era in the age of science.

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5out of 5Tara–e: The Story of a Number certainly lives up to its title! The book begins with an introduction to logarithms, highlighting the relationship between the arithmetic and geometric progressions contained therein. Then we learn how the enigmatic number e was already slyly peeking out at us, way back in the day, in the realm of compound interest. Next we have a fairly decent discussion of limits and infinity. Then, after some binomial formula gymnastics, which are aided by an obliging infinite series, e: The Story of a Number certainly lives up to its title! The book begins with an introduction to logarithms, highlighting the relationship between the arithmetic and geometric progressions contained therein. Then we learn how the enigmatic number e was already slyly peeking out at us, way back in the day, in the realm of compound interest. Next we have a fairly decent discussion of limits and infinity. Then, after some binomial formula gymnastics, which are aided by an obliging infinite series, we see why the limit of (1 + (1/n))^n, a formula related to compound interest, tends to e as n tends to infinity. A slightly more rigorous proof is fortunately included in the appendices, which, among other things, also offer a gorgeous proof of the irrationality of e. Elegant, elegant math. The author briefly discusses the Greeks’ treatment of geometry and area, and then he explores some really fascinating territory: the manner in which the very large (infinites) can be harnessed together with the very small (infinitesimals) to determine the area under a curve. This brings us to e: Grégoire de Saint-Vincent, that brilliant fiend, discovered the formula for the area under a truly stubborn little hyperbola, y = 1/x. The area in question is expressed by the logarithmic function with base e, or the natural log. You’ve just gotta love those logs! :D Next, the whole Newton/Leibniz “I invented calculus first!” bitchfit is covered. We soon discover, through differential calculus, that e is pretty badass. And get this: the exponential function e^x is equal to its own derivative. Kinky! Then a few rather run-of-the-mill physical applications of the function are perfunctorily trotted out. Blah. Now we investigate the natural log function, or the inverse of the exponential function. The logarithmic spiral, or "spira mirabilis," plotted in polar coordinates, is really quite pretty (check out that equiangular property in action!): Next we examine e as it relates to hyperbolic trig functions, and then we get to some good stuff: e^ix and Euler! Included is a simple derivation which shows that e^ix = cos x + i sin x, which thus links the exponential function (of an imaginary variable) to trigonometric functions. Sweet Jesus, how do they think of these things?? (Euler was a legend.) Also, when x = π, we obtain the stunning e^πi + 1 = 0, a formula that connects the five most important constants in mathematics. Now we’re talking! The rest of the book deals with mapping complex functions, complex analysis, polar representations of complex functions, etc. The big star of this section is how "the imaginary becomes real." Long story short: Euler managed to determine that i^i = e^-((π/2) + 2kπ), k an integer. Math is weird as hell, I’m telling you. Also, it is pointed out that hyperbolic functions are, like, super well-behaved when they play with purely imaginary variables. Well, that was a long-ass summary! Here are some pros and cons I believe are worth mentioning: Pros: The book does a much better job than most pop science books with its balance of history and actual math—it’s decidedly skewed toward the math! Also, the math in question, while detailed, can still be grasped by those who have studied a bit of calculus at the university level. Cons: The book did not really explore the more interesting real-life applications of e. Also, I had some issues with the organization of the book. For instance, the last chapter looked at different types of numbers (integers, rational versus irrational numbers, and algebraic versus transcendental numbers). It seems to me that this material ought by rights to have been presented in the beginning of the goddamn book! Seriously, I have no idea why he jammed this shit into the conclusion. Yuck city. Bottom line: if you’re keen on math, or really any STEM discipline, this book provides a decidedly comprehensive look at a number that deserves more attention than it usually receives. Also, here’s a final gift from the book I’d like to give anyone still reading. Look at this sexy girl: "…the number pi, originally defined in connection with the circle, can be expressed in terms of integers alone, albeit through an infinite process." Yes.

4out of 5Katia N–Eli Maor wrote quite a few books about the history of Mathematics. They are wonderful in combining interesting historical insights with the maths per se, but on the level of a school program. I loved his "Infinity" book. This is as well extremely erudite and fascinating. e - is irrational number which is the basis of the natural logarithm. Sounds daunting, but one can think of this number as a basis for measuring rate of change in many processes involving so called exponential growth (the rate o Eli Maor wrote quite a few books about the history of Mathematics. They are wonderful in combining interesting historical insights with the maths per se, but on the level of a school program. I loved his "Infinity" book. This is as well extremely erudite and fascinating. e - is irrational number which is the basis of the natural logarithm. Sounds daunting, but one can think of this number as a basis for measuring rate of change in many processes involving so called exponential growth (the rate of growth is proportional to the current state of the system). It is very relevant nowadays while almost everything what matters grows exponentially including information, population, pollution etc. The book is not very technical at all. It explains underlying maths. But also talks about fascinating historical characters and anecdotes. To illustrate, I will just mention here one episode: As the story goes, the Calculus were "discovered" in the 17th simultaneously by Newton in England and Leibniz on the continent. Apparently, it was huge unresolved argument who hold the priority over this discovery. The majority of academy in England claimed it was Newton and that Leibniz has stollen his ideas after seeing some of the Newton's papers. This was severely rejected by the Leibniz's defenders on the continent. Nevertheless, Leibnitz's system of notation was more intuitive and easier to understand and apply. "Knowledge of the calculus has become the dominating mathematical topic of the 18th century and quickly spread throughout the Continent. In England, where it originated, the calculus fared less well. Newton's towering figure discouraged British mathematicians from pursuing the subject with vigor. Worse, by siding completely with Newton in the priority dispute, they cut themselves off from developments on the Continent. The stubbornly stuck to Newton's dot notation, failing to see the advantages of Leibniz's differential notation. As a result, over the next hundred years, while mathematics flourished in Europe as never before, England did not produce a single first-rate mathematician. " It is so true that history does not teach people any lessons; does it?

5out of 5Bill Ward–Everyone knows about π, the ratio 3.14159... the universal constant governing circles. The constant e is just as important if not more so, but never managed to break its way into popular culture because it's a little hard to understand just what makes it so special. This book makes a valiant effort to redress that shortcoming, by explaining the history of logarithms and calculus and how the last 400 years of mathematics developed, empowered largely by this mysterious number which, before the inv Everyone knows about π, the ratio 3.14159... the universal constant governing circles. The constant e is just as important if not more so, but never managed to break its way into popular culture because it's a little hard to understand just what makes it so special. This book makes a valiant effort to redress that shortcoming, by explaining the history of logarithms and calculus and how the last 400 years of mathematics developed, empowered largely by this mysterious number which, before the invention of computers and calculators, was critical in doing any kind of serious arithmetic. Nowadays they don't even teach how logarithms are used to do multiplication - I'm 40 years old, and it was not taught when I was a kid either - but for hundreds of years the only realistic way to do it was to look up the numbers in a log table, add them up, look the sum up in another table, and get your result. This book talks about the lives of mathematicians and their discoveries, and how those built on each other to produce the knowledge we now have about the amazing world of numbers. But books like this tend to have a fatal flaw, either dumbing down the math so much that it becomes basically just biography and handwaving, or having so much math that you need an advanced math degree to understand it. This one strikes a very careful balance between those extremes. There were definitely parts where I had to stretch my brain back 20 years to high school and college calculus classes, but each of the formulas was pretty well explained, and I'd like to think you could come away from this book with some understanding even if you'd never taken any advanced math.

4out of 5Andy–One hundred and thirty pages into Eli Maor’s history of Euler’s number (e), Maor experiences what can only be described as a "John Nash moment". Here he departs from his straight-laced account to describe, at length, an imagined conversation between J. S. Bach and Johann Bernoulli. Bernoulli: That perfectly fits my love for orderly sequences of numbers. Bach: But there is a problem. A scale constructed from these ratios consists of three basic intervals: 9:8, 10:9, and 16:15. The first two are nea One hundred and thirty pages into Eli Maor’s history of Euler’s number (e), Maor experiences what can only be described as a "John Nash moment". Here he departs from his straight-laced account to describe, at length, an imagined conversation between J. S. Bach and Johann Bernoulli. Bernoulli: That perfectly fits my love for orderly sequences of numbers. Bach: But there is a problem. A scale constructed from these ratios consists of three basic intervals: 9:8, 10:9, and 16:15. The first two are nearly identical, and each is called a whole tone, or a second… But the same ratios should hold regardless of which note we start from. Every major scale consists of the same sequence of intervals. Bernoulli: I can see the confusion… This bizarre interlude aside, Maor has a difficult time keeping to the project he outlines in his introduction. Maor says he hope his book will live up to Beckmann’s A History of ∏, which he describes as model of clarity and accessibility. Unfortunately, e doesn’t lend itself easily to non-mathematical description. After a brief and entertaining history of logarithms, as Maor begins his approach to the subject at hand, his text quickly becomes mired in equations—limits, infinite series, and calculus notation. Readers equipped with some basic grounding in calculus will certainly be able to trudge through Maor’s book, and along with the history, Maor touches on many interesting applications of e—to such diverse fields as finance, number theory, physics, and architecture. All in all, though, Maor’s book is a rather whimsical attempt at a history of e, certainly nothing that will satisfy either armchair or academically-minded mathematicians.

4out of 5Elijah Oyekunle–I love this concise history of one of Mathematics' most interesting numbers. e is usually dominated by pi in mathematical history, but e also has an interesting story behind it. Calculus was required to explain and understand it, which brought the Bernoullis, Leibnitz, Newton, Euler and a lot of other scientific geniuses to tackle it. Unlike pi, which has been known for thousands of years, and which was foundational to geometry, one of Mathematics' oldest branches, e has been around for a shorter I love this concise history of one of Mathematics' most interesting numbers. e is usually dominated by pi in mathematical history, but e also has an interesting story behind it. Calculus was required to explain and understand it, which brought the Bernoullis, Leibnitz, Newton, Euler and a lot of other scientific geniuses to tackle it. Unlike pi, which has been known for thousands of years, and which was foundational to geometry, one of Mathematics' oldest branches, e has been around for a shorter period of time (about 400 years), and deals with a bunch of things like irrationality, infinity and stuff that ancient mathematicians never liked to think much about. I always find interesting the story of Hippasus, a Pythagorean who is famous for getting drowned by other Pythagoreans for his threat to expose irrationality. Although a lot of stuff in the book was over my head and I steadily refused the urge to read the Appendices, I still think this book is a good work of mathematical history.

4out of 5Jeffrey–OK, so books on math, not going to become national best sellers by any stretch of the imagination. But any story in the field of math be it zero, 'e,' Phi, PI tells us more about that mystical, insightful language that can tell us so much about the why's and what's of our surroundings, as well as provide the more practical to suit our human needs. Math is interesting in the sense that it dictates to the mathematician not the mathematician to it to determine outcome. ie: in string theory, the mat OK, so books on math, not going to become national best sellers by any stretch of the imagination. But any story in the field of math be it zero, 'e,' Phi, PI tells us more about that mystical, insightful language that can tell us so much about the why's and what's of our surroundings, as well as provide the more practical to suit our human needs. Math is interesting in the sense that it dictates to the mathematician not the mathematician to it to determine outcome. ie: in string theory, the math tells the mathematician that not only is a fourth dimension needed but up to a seventh. So, to the book. Maor has done a great job giving us some background on 'e' and its beginnings in logarithmic use. And even though 'e's use can be found in diverse places--"the interest earned in a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis"--its significance, only second to PI in importance, as a number is greatly and clearly expressed by Maor. It's written for the non-mathematician, no great depth of understanding needed to get the points here. Some anecdotes and diversions to bring home points made. Good effort.

5out of 5Ben Pace–Enjoyable skim through the basics of logarithms, conic sections, calculus, and various other areas of mathematics relating to e. Not a textbook, so don't read this to learn those subjects, only to glance at them. The historical aspects add a narrative element, and of course the writing is far more pleasant than a textbook too. The background given, and also the original explanations, helped me to understand some of the concepts better, so I am glad that I read it. I will only be giving it a curs Enjoyable skim through the basics of logarithms, conic sections, calculus, and various other areas of mathematics relating to e. Not a textbook, so don't read this to learn those subjects, only to glance at them. The historical aspects add a narrative element, and of course the writing is far more pleasant than a textbook too. The background given, and also the original explanations, helped me to understand some of the concepts better, so I am glad that I read it. I will only be giving it a cursory glance though. (Subject to edit on completion)

5out of 5Stanley Xue–Great book to explore mathematics from a different perspective (recreational rather than traditional mathematics education). Even suitable if you haven't touched and been learning more maths for a while. Many of the explanations were built from first principles. Although there was a lot of overlap initially with mathematics covered in high school cirricula (e.g. logarithms, compound interest formula, limits & Zeno's paradox, differentiation from first principles, binomial theorem/Pascal's triang Great book to explore mathematics from a different perspective (recreational rather than traditional mathematics education). Even suitable if you haven't touched and been learning more maths for a while. Many of the explanations were built from first principles. Although there was a lot of overlap initially with mathematics covered in high school cirricula (e.g. logarithms, compound interest formula, limits & Zeno's paradox, differentiation from first principles, binomial theorem/Pascal's triangle, differentiation and integration). Similarly to An Imaginary Tale, this subject matter was approached in a chronological manner, with stories about the characters and mathematicians involved in the story of e. This improved the ease of the read and helped maintan my interest in combination with other general trivial facts and case studies e.g. the story of the Bernoulli family, the tables of logarithms. There was ample new subject matter especially in the latter half of the book for me (stuff that wasn't covered in high school, wasn't proven and accepted as fact, or just forgotten by me): spira mirabillis, squaring of the hyperbola (proof for area under hyperbola without use of calculus), hyperbolic functions, mapping of complex functions etc. It was especially satisfying to read about the relationship between e and pi (e.g. Euler's formula); as well as e appearing in the Prime Number Theorem; AND THAT YOU CAN EVALUATE LOGARITHMS OF NEGATIVE NUMBERS (explanation also in An Imaginary Tale (below)). Would recommend reading in conjunction with An Imaginary Tale (a book about the imaginary number: i) - although the material of the latter seems to be more advanced. Having only read that book a month ago, I seem to have forgotten some of the theorems and proofs within. As such, this book was great to remind me of those theorems and the beauty of their proofs. (NB: some overlap in the content of the book e.g. Euler's thoerem, Laplace's equations, hyperbolic functions). Maybe I wish that there was more maths in this book. Some proofs seem to be glossed over and "outside the scope of this book". Some of the explanations seem less clear than those within An Imaginary Tale. Maybe this is why I rate this book 4 starts instead of 5. (As well since the novelty of a book (that is not a textbook) fiddling with a lot of maths has been attenuated for me). I do wish there were more math equations/proofs rather than maths mixed in with wordy explanations. Although I'm not sure which one I retain better since it seems that a lot of the proofs and examples in An Imaginary Tale have already been lost on me.

5out of 5andrew y–As said by others - picked this up wanting to understand a complex mathematical topic, got this and also an awesome historical overview of the development of the calculus and more over hundreds of years. Awesome!

5out of 5Jennifer–Too. Much. Calculus. I was hoping this would be more like The Golden Ratio: The Story of Phi, the World's Most Astonishing Number, but it wasn't. For one thing, this book has differential equations. A lot of them. As a STEM major, I did study calculus at the university level (but not Dif Eq), but this was still hard going. What really helped get me through the book were the historical anecdotes, and the parts of the book I was able to follow well were also well-done. Too. Much. Calculus. I was hoping this would be more like The Golden Ratio: The Story of Phi, the World's Most Astonishing Number, but it wasn't. For one thing, this book has differential equations. A lot of them. As a STEM major, I did study calculus at the university level (but not Dif Eq), but this was still hard going. What really helped get me through the book were the historical anecdotes, and the parts of the book I was able to follow well were also well-done.

5out of 5Tim–Maor's account of the place of e, the base of the natural logarithms, in the history of mathematics provides a peek inside a mathematician's brain. More connected by mathematical ideas than by chronology or the usual social, cultural, economic, or political themes taken up by historians, Maor's book opened vistas in the calculus I did not see when I first ploddingly confronted derivatives and integrals some decades ago. He thoroughly covers the differing views of Newton and Leibniz as they devel Maor's account of the place of e, the base of the natural logarithms, in the history of mathematics provides a peek inside a mathematician's brain. More connected by mathematical ideas than by chronology or the usual social, cultural, economic, or political themes taken up by historians, Maor's book opened vistas in the calculus I did not see when I first ploddingly confronted derivatives and integrals some decades ago. He thoroughly covers the differing views of Newton and Leibniz as they developed the calculus. He discusses some of the special characteristics of e revealed in the fact that the exponential function is its own derivative. He shows how e appeared in nature and the arts - musical scales, the spiral mirablis, a hanging chain, the parabolic arc of a projectile, the Gateway Arch. More than other of recent books focused on a particular number, Maor explores the mathematics of e with a mathematician's interest. But metaphysics creeps in as it seems to in discursive accounts of mathematical developments and achievements. Numbers - in particular special numbers like e - have been imbued with mystical connections to larger or hidden things. This account of e raises the questions again, "What is this language of numbers that humans have developed and how is this language linked to the world 'out there'?" In one sense, the number e, like its more famous companion pi, turns out to be not only an irrational number but also non-algebraic - not a solution (root) of a polynomial equation. Such numbers are called transcendental, meaning merely 'beyond algebraic'. In the end, Maor's story of e is an account of human activity in a world of patterns. And it is an excellent companion to a course in calculus.

5out of 5melydia–Like its more famous cousin pi, e is an irrational number that shows up in unexpected places all over mathematics. It also has a much more recent history, not appearing on the scene until the 16th century. My favorite parts of this book were the historical anecdotes such as the competitive Bernoullis and the Nerwton-Leibniz cross-Channel calculus feud. Unfortunately, this math history text is much heavier on the math than the history, including detailed descriptions of limits, derivatives, integ Like its more famous cousin pi, e is an irrational number that shows up in unexpected places all over mathematics. It also has a much more recent history, not appearing on the scene until the 16th century. My favorite parts of this book were the historical anecdotes such as the competitive Bernoullis and the Nerwton-Leibniz cross-Channel calculus feud. Unfortunately, this math history text is much heavier on the math than the history, including detailed descriptions of limits, derivatives, integrals, and imaginary numbers. The trouble with this large number of equationsis that if you’re already familiar with the concepts you’ll be doing a lot of skimming, but if the subject is confusing then reading this book will probably not give you any new insights. In short, as much as I normally enjoy books about math and science, this particular one felt too much like a textbook. Recommended only for those folks with a very strong love for the calculus and related topics.

5out of 5Aakash Subhankar Bhowmick–The book takes you through an amazing journey of time in which you will be fascinated and humbled by the efforts which mathematician have put in to develop mathematics as it is today. The book is perfect to arouse interest in mathematics in your children, and to make them realize that more than its regular textbook form, mathematics is fun, inspiring and beautiful.

5out of 5Dan–Maor did not do a good job at staying remotely on-topic. This would be better advertised as a history of calculus, as more time was devoted to that than to e. While the historical content of the book is certainly fascinating, it is not what I signed up for when I started reading.

4out of 5Ari–I found this basically unreadable. It oscillated too quickly between "history" and "refresher of AP calculus" and lacked any real unifying themes. It felt very rambly. The author has a lot of facts more or less related to logarithms, or exponentials, or infinite series, and wants to share them all. I found this basically unreadable. It oscillated too quickly between "history" and "refresher of AP calculus" and lacked any real unifying themes. It felt very rambly. The author has a lot of facts more or less related to logarithms, or exponentials, or infinite series, and wants to share them all.

4out of 5Swhite–This is a fairly straightforward book, doing essentially what it set out to do. It gives you a history of how *e* came to be and shows you how it became increasingly important in mathematics. The one interesting wrinkle is the author's view of the Newton & Leibniz, where the author clearly takes a pro Leibniz stand. Having read other books by other authors with a distinctly different tone, I found the author's opinions troubling. For one, the author seemed to be somewhat dismissive of physics an This is a fairly straightforward book, doing essentially what it set out to do. It gives you a history of how *e* came to be and shows you how it became increasingly important in mathematics. The one interesting wrinkle is the author's view of the Newton & Leibniz, where the author clearly takes a pro Leibniz stand. Having read other books by other authors with a distinctly different tone, I found the author's opinions troubling. For one, the author seemed to be somewhat dismissive of physics and other applied aspects of math. For example, the author says, in so many words, that Newton's syntax and approach were polluted by the real world applications to which it was applied, while Leibniz approached calculus with the eye of a true mathematician. And the one thing the book really has trouble explaining is why Leibniz died somewhat in obscurity while Newton was given great honors. Both had equal numbers of defenders and detractors. Why were Germany and France not honoring Leibniz and giving him accolades? The answer is that the author left out critical pieces of information and let his bias for mathematics against applied sciences warp his view of the players. One accusation the author makes is that England essentially went into a temporary dark period for the development of mathematics until the 1830s because of their unwillingness to adopt the superior notation and reasoning made by Leibniz. But did that slow the advancement of physics, chemistry, engineering, mechanics in England? Leibniz was a giant of mathematics and probably better at the theoretical aspects of Calculus, but Newton had F = ma and history rightfully judges Newton the giant and Leibniz a far behind runner up. Also, though Leibniz wrote the superior Calculus textbook with superior insight and syntax, Newton was far better at actually solving challenging math problems with real world implications. And finally, though I believe Leibniz should get equal claim for developing Calculus and I disagree with those who wish to give majority credit to Newton, Leibniz and his supporters used dishonest methods, such as back dating documents, to make their case. They also wrote anonymous scurilious attacks which they denied they wrote and then were later found out to have actually written. Or to put it another way, Leibniz and his defenders behaved in ways that were perceived by others to be dishonorable. There is one interesting subtext that the author does not really go into as well. In later years, Leibniz and Newton did make up to a certain extent and acknowledged each others roles as being vital. The real controversies started when Leibniz and Newton had gotten quite old and the dispute was taken up by other players. Then the controversy had more to do with politics than any real interest to determining who was responsible for what.

5out of 5Guardingnome–I can trace all of my interest, and success, in mathematics back to this book. I read it at a far too young age, and harassed my friends with my otherworldly knowledge of numbers and mathematics for years. Eli Maor is extremely capable at distilling complex concepts into simple and intuitive explanations, and weaving the human nature of discovery into the story of this number. e, the number, is visible so much in the world around us, and this book does an excellent job at explaining the significan I can trace all of my interest, and success, in mathematics back to this book. I read it at a far too young age, and harassed my friends with my otherworldly knowledge of numbers and mathematics for years. Eli Maor is extremely capable at distilling complex concepts into simple and intuitive explanations, and weaving the human nature of discovery into the story of this number. e, the number, is visible so much in the world around us, and this book does an excellent job at explaining the significance and peculiarity of this relation. I cannot stress enough that this book should not be passed up, especially by curious children.

4out of 5David–Absolutely brilliant. Among my favorite books. It has everything---from the infamous Newton/Leibniz controversy and the first derivation of Euler's constant from compound-interest calculations to the rectification of the logarithmic spiral and the Cauchy-Riemann equations for (complex) analytic functions. The appendix alone is nearly worth the price of the book. A true gem. Riveting and well written. Essential reading. Absolutely brilliant. Among my favorite books. It has everything---from the infamous Newton/Leibniz controversy and the first derivation of Euler's constant from compound-interest calculations to the rectification of the logarithmic spiral and the Cauchy-Riemann equations for (complex) analytic functions. The appendix alone is nearly worth the price of the book. A true gem. Riveting and well written. Essential reading.

4out of 5Matt–This book is, I think, as good as it could be given its dry subject matter. The histotical portion of the book was well written and well researched, but it's not a page-turner. The math was well explained, although, I think you had better understand calculus to get much out of it. In his preface, Maor's stated goal is for the book to be "accessible to readers with only a modest background in mathematics". In that, I think he falls well short. This book is, I think, as good as it could be given its dry subject matter. The histotical portion of the book was well written and well researched, but it's not a page-turner. The math was well explained, although, I think you had better understand calculus to get much out of it. In his preface, Maor's stated goal is for the book to be "accessible to readers with only a modest background in mathematics". In that, I think he falls well short.

5out of 5Karina–Well that was quick. Skimmed thru to cherry pick what was accessible to me as a non math background person. My main interest was the imaginary number represented by "e" or Euler's number 2.718281828... that has to do with a compound interest problem. It is the limit of (1 + 1/n)n as n approaches infinity, an expression that arises in the study of compound interest. Now I have a feeling and basic understanding of "e" which was my goal. Well that was quick. Skimmed thru to cherry pick what was accessible to me as a non math background person. My main interest was the imaginary number represented by "e" or Euler's number 2.718281828... that has to do with a compound interest problem. It is the limit of (1 + 1/n)n as n approaches infinity, an expression that arises in the study of compound interest. Now I have a feeling and basic understanding of "e" which was my goal.

5out of 5Daniel–Interesting enough. Best thing about the book IMO is the appendix that offers proofs for the existence of the number in its earliest form (i.e., limit of (1+1/n)^n). I always find the typical discussions of e or of that limit to be circular, so it's nice to have a from-scratch defense of the number! Interesting enough. Best thing about the book IMO is the appendix that offers proofs for the existence of the number in its earliest form (i.e., limit of (1+1/n)^n). I always find the typical discussions of e or of that limit to be circular, so it's nice to have a from-scratch defense of the number!

5out of 5Quinton Baran–I started this book many years ago, and got about half way in, and realized that I was struggling to understand the math concepts. This led me to reviewing my college algebra, something that I still have on my project list - a long term project list as it turns out. I am culling this from my current reading list for now.

4out of 5Ashar Malik–This is a great book. It talks about "e" and its history and recent this is compared to the its counterpart, pi. The book delves through the works of many mathematicians to bring together a coherent history of this amazing number. The book is written in a simple language, with some maths, and thus many lay users will find the read quite friendly. I would definitely recommend it to everyone. This is a great book. It talks about "e" and its history and recent this is compared to the its counterpart, pi. The book delves through the works of many mathematicians to bring together a coherent history of this amazing number. The book is written in a simple language, with some maths, and thus many lay users will find the read quite friendly. I would definitely recommend it to everyone.

5out of 5Stan–I'm fascinated by the concept of this number and how it appears in our natural world. But this book was too technical for me, and I have a bachelor's degree in engineering. Granted, my calculus days are far behind me. But even so, there was far too many equations and proofs for my liking. I was hoping for more of a story about this number, and less of a proof. Oh well I'm fascinated by the concept of this number and how it appears in our natural world. But this book was too technical for me, and I have a bachelor's degree in engineering. Granted, my calculus days are far behind me. But even so, there was far too many equations and proofs for my liking. I was hoping for more of a story about this number, and less of a proof. Oh well

5out of 5Brandon Meredith–I read about half this book and then put it down. It had some somewhat interesting stuff near the beginning but then started treading over some territory I’ve seen time and again, much of it only tangentially related to the title.

4out of 5Ron Z.–A good mix of history and math to allow the reader to see how ideas were shared and advanced. I re-learned Calculus in a few pages here where it took me months in college. If you're interested in math, proofs and logic, you'll enjoy this book. A good mix of history and math to allow the reader to see how ideas were shared and advanced. I re-learned Calculus in a few pages here where it took me months in college. If you're interested in math, proofs and logic, you'll enjoy this book.

4out of 5Greg–Really enjoyed this. Hard to say how fun it would be if you haven't taken a fair bit of calculus+, but I think he did an admirable job of keeping it casual. For me, beyond being an interesting look at the natural logarithm it was a really fun nostalgic journey through the math courses I've taken. Really enjoyed this. Hard to say how fun it would be if you haven't taken a fair bit of calculus+, but I think he did an admirable job of keeping it casual. For me, beyond being an interesting look at the natural logarithm it was a really fun nostalgic journey through the math courses I've taken.

5out of 5Annette–I enjoyed the writing and the connections between mathematical topics. I was not as interested in following the many derivations/proofs.

4out of 5Aleksandra Singer–The writing style was sometimes a little dry, but I found the actual material fun and interesting. I liked the balance between historical anecdotes and mathematical formulas.

4out of 5Dani Ollé–Great history book of mathematics which explains also the mathematical concepts themselves