Coolidge, Julian Lowell (1873–1954)

US geometrician. He wrote many mathematical textbooks, in which he not only reported his results but also described the historical background, together with contemporary developments. Coolidge's first book (1909) was on non-Euclidean geometry. He was especially interested in the use of geometry in the investigation of complex numbers. Coolidge also wrote his first paper on probability theory in 1909, in which he examined certain problems in game theory. Together with several later studies on statistics, this work was included in his 1925 book on probability – one of the first on the subject to be published in English.

Coolidge was born in Brookline, Massachusetts. He studied at Harvard and at several universities in Europe, including Oxford. From 1900 he taught at Harvard, where he became professor in 1918 and remained until 1940. His first work on the algebraic theory of curves appeared in 1915, and a book in 1931. Work on two classical geometrical figures – the circle and the sphere – also led to the writing of a book in 1916. His last book was a historical text in 1949.