Henri Poincaré

Henri Poincaré was the last mathematician to command the whole of his subject, founding topology and the qualitative theory of differential equations, discovering chaos in the three-body problem, and arriving at much of special relativity before Einstein. He also wrote, for the general reader, the books that made the philosophy of science a subject. Science and Hypothesis argues that the axioms of geometry are conventions, neither true nor false; Science and Method describes how mathematical discovery happens, with the famous account of the idea that came as he stepped onto a bus. His cousin Raymond was president of France.