The French philosopher, playwright, and novelist Denis Diderot (1713-1784) is best known as the editor of the Encyclopédie.

On Oct. 15, 1713, Denis Diderot was born in Langres, Compagne, into a family of cutlers, whose bourgeois traditions went back to the late Middle Ages. As a child, Denis was considered a brilliant student by his Jesuit teachers, and it was decided that he should enter the clergy. In 1726 he enrolled in the Jesuit college of Louis-le-Grand and probably later attended the Jansenist Collège d'Harcourt. In 1732 he earned a master of arts degree in philosophy. He then abandoned the clergy as a career and decided to study law. His legal training, however, was short-lived. In 1734 Diderot decided to seek his fortune by writing. He broke with his family and for the next 10 years lived a rather bohemian existence. He earned his living by translating English works and...