The reign of philosophical optimism, or the doctrine of the ‘best of all possible worlds’ in modern European philosophy began in 1710 with the publication of Leibniz’s Theodicy, about God’s goodness and wisdom, divine and human freedom, and the meaning of evil. It ended on November 1, 1755 with the Lisbon Earthquake, which was followed by numerous attacks against optimism, starting with Voltaire’s Poème sur le désastre de Lisbonne and Candide. The years between both events were intense. In this book, Hernán D. Caro offers the first comprehensive survey of the criticisms of optimism before the infamous earthquake, a time when the foundations of what has been called the ‘debacle of the perfect world’ were first laid.