PREFACE Of all the modern "Keys to Fortune" none more easily turns the tumblers of the lock of Life than Perseverance. This quality Plutarch described as all-powerful. Said he, Perseverance is the best friend and ally of those who use properly the opportunities that it presents, and the worst enemy of those who rush into action before it summons them.'' PREFACE Of all the modern "Keys to Fortune" none more easily turns the tumblers of the lock of Life than Perseverance. This quality Plutarch described as all-powerful. Said he, Perseverance is the best friend and ally of those who use properly the opportunities that it presents, and the worst enemy of those who rush into action before it summons them.''