American mathematical physicist who was awarded the Fields Medal in 1990 for his work in superstring theory (string theory). He also received the Dirac Medal from the International Centre for Theoretical Physics (1985).

Witten was educated at Brandeis University (B.A., 1971) in Waltham, Massachusetts, and Princeton University (M.A., 1974; Ph.D., 1976) in New Jersey. He held a fellowship at Harvard University (1976–77), was a junior fellow in the Harvard Society of Fellows (1977–80), and held a MacArthur Foundation fellowship (1982). He held an appointment at Princeton (1980–87) before moving to the Institute for Advanced Study, Princeton, in 1987.

Witten was awarded the Fields Medal at the International Congress of Mathematicians in Kyōto, Japan, in 1990. His early research interests were in electromagnetism, but he soon developed an interest in what is now known as superstring theory in mathematical physics. He made significant contributions to Morse theory, supersymmetry, and knot theory. Additionally, he explored the relationship between quantum field theory and the differential topology of manifolds (manifold) of two and three dimensions. With the physicist Nathan Seiberg he produced a family of partial differential equations (partial differential equation) that greatly simplified Simon Donaldson (Donaldson, Simon Kirwan)'s approach to the classification of four-dimensional manifolds.

Witten's publications include, with Sam B. Treimen, Roman Jackiw, and Bruno Zumino, Current Algebra and Anomalies (1985) and, with Michael B. Green and John H. Schwarz, Superstring Theory (1987).