It was 1733 when the poet and philosopher Voltaire met Emilie du Châtelet, a beguiling—and married—aristocrat who would one day popularize Newton’s arcane ideas and pave the way for Einstein’s theories. In an era when women were rarely permitted any serious schooling, this twenty-seven-year-old’s nimble conversation and unusual brilliance led Voltaire, then in his late thirties, to wonder, “Why did you only reach me so late?” They fell immediately and passionately in love.

Through the prism of their tumultuous fifteen-year relationship we see the crumbling of an ancient social order and the birth of the Enlightenment. Together the two lovers rebuilt a dilapidated and isolated rural chateau at Cirey where they conducted scientific experiments, entertained many of the leading thinkers of the burgeoning scientific revolution, and developed radical ideas about the monarchy, the nature of free will, the subordination of women, and the separation of church and state.