Denis Diderot (1713-1784) was the most versatile of the Philosophes. He wrote on philosophy, science, technology, theology, and education, and he also wrote plays, novels, essays, and art and dramatic criticism. He was the typical Philosophe who rejected all authority and tradition that interfered with free inquiry and violated the natural rights of man. He believed that religious intolerance was the greatest enemy of progress, and he pleaded passionately for toleration and intellectual freedom. Sainte-Beuve called Diderot "the Spokesman of the Century."
Diderot's life was a hard one, an affair of ups and downs. When he was in his early years as a writer, he was sometimes on the verge of starvation, and though he became a famous author and was an indefatigable worker, he never had more than a modest income, and he was never elected to the French Academy. Also he spent a term in prison. If on the one hand, he sometimes did not know where his next meal was coming from, on the other, he was later for a time a favorite at the court of Catharine the Great of Russia. Diderot's head was always full of all sorts of ideas, plans, projects, and dreams.