Richard S. Westfall (April 22, 1924 – August 21, 1996) was an American academic, biographer and historian of science. He is best known for his biography of Isaac Newton and his work on the scientific revolution of the 17th century.
Born in Fort Collins, Colorado, Westfall graduated from high school in 1942 and enrolled at Yale University. His time at Yale was interrupted by two years of service in World War II, but he returned to complete his B.A. degree in 1948. He subsequently earned M.A. and Ph.D. degrees from Yale, with a dissertation entitled Science and Religion in Seventeenth Century England. The work was an early example of his lifelong interest in the history of science and its relationship to religion.
Westfall taught history at various universities in the 1950s and 1960s: California Institute of Technology (1952–53), State University of Iowa (1953–57), and Grinnell College (1957–63). He began teaching at Indiana University in 1963 and worked his way up the faculty ranks until his retirement in 1989 as Distinguished Professor Emeritus. He died in 1996 in Bloomington, Indiana at the age of 72.
In 1980 Westfall published what is widely regarded as the definitive biography of Isaac Newton, Never at Rest. Westfall considered Newton a driven, neurotic, often humorless and vengeful individual. Despite these personal faults, Westfall ranked Newton as the most important man in the history of western European civilization. Westfall published a condensed and simplified version of the biography as The Life of Isaac Newton in 1993.