sentences:  His Ph.D. thesis, entitled "Triangulating homotopy equivalences", was written under the supervision of William Browder, and was a contribution to surgery theory.He was a permanent member of the Institut des Hautes Études Scientifiques from 1974 to 1997.Sullivan is one of the founders of the surgery method of classifying high-dimensional manifolds, along with Browder, Sergei Novikov and C. T. C. Wall.