In the spring of 1672, the German philosopher and mathematician Gottfried Wilhelm Leibniz arrived in Paris on a furtive diplomatic mission. That project was abandoned quickly, but Leibniz remained in Paris with a singular goal: to get the most out of the city’s intellectual and cultural riches. He benefited, above all, from his friendships with France’s two greatest philosopher-theologians of the period, Antoine Arnauld and Nicolas de Malebranche. The interactions of these three men would prove of great consequence not only for Leibniz’s own philosophy but for the development of modern philosophical and religious thought. Despite their wildly different views and personalities, the three philosophers shared a single, passionate concern: resolving the problem of evil. Why is it that, in a world created by an allpowerful, all-wise, and infinitely just God, there is sin and suffering? Why do bad things happen to good people, and good things to bad people? This is the story of a clash between radically divergent worldviews. But it is also a very personal story. At its heart are the dramatic-and often turbulent-relationships between three brilliant and resolute individuals. In this lively and engaging book, Steven Nadler brings to life a debate that obsessed its participants, captivated European intellectuals, and continues to inform our ways of thinking about God, morality, and the world.