John Crerar (krē´rər), 1827–89, American capitalist and philanthropist, b. New York City. Crerar was a manufacturer in Chicago, and gave liberally to many causes. He is remembered chiefly for the John Crerar Library, a scientific and technical reference library in Chicago, for which he provided in his will. The library has special collections on medicine, Chinese literature, Dutch history, floriculture, the history of the women's movement, trade unions, and social science in general. It is noted for its fine bibliographical work.