Bill Thurston was an American mathematician (Fields Medalist, 1982) who made important contributions to the theory of orbifolds, the theory of foliations, low-dimensional topology (especially in three dimensions), and to geometric group theory. He is perhaps best known for his geometrization conjecture (which was proved by Thurston in special cases, and by Richard Hamilton and Grigori Perelman in complete generality, and which in turn implies the Poincaré conjecture).
The theory of foliations of codimension greater than one, Comm. Math. Helv. 49 (1974), 214-231.
Existence of codimension-one foliations, Annals of Math. (2), 104 (1976), 249-268.
Three-Dimensional Geometry and Topology, Vol. I (ed. Silvio Levy), Princeton University Press, 1997.
On proof and progress in mathematics, Bull. AMS 30 (1994), 161-177. (web)