Maurice Kraitchik

Maurice Kraitchik (born April 21, 1882 in Minsk, died Aug. 19, 1957 in Brussels) was a Belgian mathematician and populariser. His main interests were the theory of numbers and recreational mathematics.

He is famous for having inspired the two envelopes problem in 1953, with the following puzzle in La mathématique des jeux:

Kraitchik wrote several books on number theory during 1922-1930 and after the war, and from 1931 to 1939 edited Sphinx, a periodical devoted to recreational mathematics.

During World War II, Kraïtchik emigrated to the United States, where he taught a course at the New School for Social Research in New York City on the general topic of "mathematical recreations."

Kraïtchik was « agrégé » of the Free University of Brussels, engineer at the “Société Financière de Transports et d'Entreprises Industrielles (Sofina)”, and director of the “Institut des Hautes Etudes de Belgique”.

Among his publications were the following:

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