"A colorful reinterpretation…. Stewart's wit and profluent prose make this book a fascinating read."—Publishers Weekly, starred review

Philosophy in the late seventeenth century was a dangerous business. No careerist could afford to know the reclusive, controversial philosopher Baruch de Spinoza. Yet the wildly ambitious genius Gottfried Wilhelm Leibniz, who denounced Spinoza in public, became privately obsessed with Spinoza's ideas, wrote him clandestine letters, and ultimately met him in secret.

"In refreshingly lucid terms" (Booklist) Matthew Stewart "rescues both men from a dusty academic shelf, bringing them to life as enlightened humans" (Library Journal) central to the religious, political, and personal battles that gave birth to the modern age. Both men put their faith in the guidance of reason, but one spent his life defending a God he may not have believed in, while the other believed in a God who did not need his defense. Ultimately, the two thinkers represent radically different approaches to the challenges of the modern era. They stand for a choice that we all must make.