Andrei Kolmogorov is one of the most important mathematicians of the 20th century. He was born on April 25, 1903 in Tambov, Russia. Kolmogorov's mother died in childbirth, and so he was raised by his mother's sister. He attended Moscow State University, studying mathematics, history, and metallurgy. By the time he received the PhD degree in 1925, Kolmogorov had published 18 papers, including work on some of the most important problems in probability: the three series theorem, martingale inequalities, versions of the strong law of large numbers, and the law of the iterated logarithm.
Kolmogorov was appointed professor of mathematics at Moscow State University in 1931. In 1933, he published one of the most important works in probability, Grundbegriffe der Wahrscheinlichkeitsrechnung (Foundations of Probability Theory), which defined probability axiomatically and established probability theory as a branch of measure theory. He also did foundational work in stochastic processes, including Markov processes, named for Andrei Markov.
In addition to probability, Kolmogorov made important contributions in topology, algebraic topology, functional analysis, dynamical systems, fluid dynamics, and even mathematics education. Outside of mathematics, Kolmogorov continued his interests in history and poetry.
Kolmogorov was elected to just about every important scientific society, including the Soviet Academy of Sciences, The American Academy of Arts and Sciences, the London Mathematical Society, and the French Academy of Sciences. Kolmogorov received numerous awards and honorary degrees.
Kolmogorov died on October 20, 1987 in Moscow.