Candide came into being largely because of Voltaire's great dissatisfaction with the explanation for the problem of evil and human suffering provided by the philosophers of his day. Published in 1759 when Voltaire was 65, Candide was a direct attack on the school of optimism championed by German philosopher Gottfried Leibniz and English poet Alexander Pope and popularized in the adventure and romance novels of the period. Optimism, Voltaire's young hero, Candide, asserts, is "the mania for asserting that all is well when one is not." The danger of optimism, Voltaire believed, lies in its essentially passive response to life. If God has given human beings "the best of all possible worlds," as Leibniz claimed, and if everything that happens is somehow for the best, then to what point is human choice and action?

In this well-balanced study, Mason relates the events in Voltaire's personal life and in the world around him that contributed to his revolt: the death of his closest companion; his exile from Paris; the catastrophic Lisbon earthquake of 1755; the eruption and often ruthless conduct of the Seven Years' War. The real-life hardships of psychological pain, natural disaster, and war, Voltaire found, could not be rationalized away by philosophy.