Timothy Gowers is the Rouse Ball Professor of Mathematics at Cambridge University. He works in combinatorics, combinatorial number theory, and in the theory of Banach spaces, and has made fundamental contributions to these fields. He has solved many important problems on the structure of Banach spaces, and in combinatorics he has worked on difficult problems involving randomness and regularity in number theory. His exceptional insight and clarity have led to remarkable advances in these theories, arrived at by novel and creative combinations of analytic techniques and combinatorial ingenuity. His achievements were recognised in 1998 by the award of a Fields Medal (in mathematics, the equivalent of a Nobel Prize).