1580 saw the publication of Montaigne’s Essays, which the Introduction identifies as the first philosophical work in French. Montaigne was fluent in Latin, the language of scholarship, so what was the significance of his writing in the vernacular? During the early modern period, French philosophy covered what we would now think of as science, along with theology, metaphysics, and ethics. During the Enlightenment and the French Revolution, philosophy became associated with radical politics and intellectualism. After the First World War, French philosophers embraced existential ideas from Germany and further east. What impact would ‘French theory’ have on the twentieth century?