born March 21, 1768, Auxerre, France died May 16, 1830, Paris French mathematician and Egyptologist. While an engineer on Napoleon's Egyptian expedition, he conducted (1798-1801) anthropological investigations and wrote the preface to the monumental Description de l'Égypte, whose publication he oversaw (1809-28). In 1808 he was created a baron by Napoleon. In mathematics he is primarily known for his work in heat conduction (1807-22), for his use of the Fourier series to solve differential equations, and for the related concept of the Fourier transform. As a scientist and humanist, he epitomized the spirit of French intellectualism of the Revolutionary era