Comte Joseph-Louis Lagrange is considered by many historians to be the foremost mathematician of 18th century Europe. He invented the calculus of variations, laid the foundation for modern mechanics, and made major contributions to the fields of algebra and number theory. He is also credited with establishing the standard of the metric system, now in widespread use throughout the world. Lagrange is highly regarded both for the originality of his work and the rigor and generality of his mathematical proofs.

Lagrange was born in Turin, Italy, on January 25, 1736. His father, a Frenchman, served as Treasurer of War in Sardinia, and his mother, Marie-Therese Gros, was the daughter of a wealthy Italian physician. Lagrange was the youngest of 11 children and the only one to survive past infancy. His early schooling focused on the classics, and although he read the works of Euclid and Archimedes, Lagrange displayed little initial interest...