Pierre Simon Laplace, the most influential of the French mathematician-scientists of his time, made many important contributions to celestial mechanics, the theory of heat, the mathematical theory of probability, and other branches of pure and applied mathematics. He was born into a Normandy family of well-to-do peasant farmers and merchants. Intended for an ecclesiastical career, he matriculated at the University of Caen in theology but, discovering his aptitude for mathematics, departed for Paris at age nineteen bearing a letter from his instructors to the mathematician d'Alembert, a leading intellectual figure in prerevolutionary France.

D'Alembert, impressed by Laplace, took him on as his protégé and obtained an appointment for him as a professor of mathematics at the École Militaire, where he taught mathematics to teenage cadets. In this position, Laplace was also expected to present his work to the Académie Royal...