Leopold Kronecker's approach to mathematics can best be described in perhaps his most famous words, spoken in 1886 in Berlin: "The integer numbers were made by God, everything else is the work of man." Kronecker believed that all mathematics could be reduced to and explained by finite whole numbers only, and that irrational and transcendental numbers and any related proofs and theories involving them did not exist.

Kronecker was born into a well-to-do family, and through inheritance and business interests, he remained independently wealthy throughout his life. He developed a keen interest in mathematics when in school at the Liegnitz Gymnasium (secondary school). Here, he met teacher Ernst Kummer, whom he would work with for the greater part of his mathematical career.

In 1841, Kronecker enrolled at Berlin University to study mathematics, philosophy, and astronomy. After a brief stint at the University of Breslau, where he once again studied under...