Georg Cantor, a mathematician who created set theory and a corresponding theory of transfinite numbers, revolutionized mathematics at the end of the nineteenth century with his ideas about the infinite, which were to be of profound significance not only for mathematics but for philosophy and many allied disciplines as well.

He was born on March 3, 1845, in St. Petersburg, Russia, to Georg Woldemar Cantor, a successful merchant and the son of a Jewish businessman from Copenhagen, and Maria Anna Böhm, who came from a family of notable musicians and was a Roman Catholic. But Cantor's father, raised in a Lutheran mission, was a deeply religious man and passed his own strong convictions on to his son. Later in life, Cantor's religious beliefs would play a significant role in his steadfast faith in the correctness of his controversial transfinite set theory, just as his mother's...