Timothy Gowers proves in 1996, in Geometric and Functional Analysis, a general dichotomy on the structure of infinite-dimensional Banach spaces, culminating a line of work developed together with Bernard Maurey from 1992-93 onward. The result answers several structural questions that had been open for decades in Banach space theory, combining, in a novel way, functional-analysis techniques with combinatorial methods — an approach characteristic of Gowers's later work in additive combinatorics. Gowers received the Fields Medal in 1998.