What Is Mathematics?

What Is Mathematics? is a mathematics book written by Richard Courant and Herbert Robbins, published in England by Oxford University Press. It is an introduction to mathematics, intended both for the mathematics student and for the general public.

First published in 1941, it discusses number theory, geometry, topology and calculus. A second edition was published in 1996 with an additional chapter on recent progress in mathematics, written by Ian Stewart. A Spanish translation of the second edition, ¿Qué Son Las Matemáticas?, was published in 2002. Millions of copies of unauthorised Russian and Chinese editions have been printed.

Although Robbins wrote most of the book, he received almost none of the royalties. Courant owned the copyright, and passed almost none of the money on to Robbins. Michael Katehakis, remembers Robbins interest in the literature and Tolstoy in particular and he is convinced that the title of the book is most likely due to Robbins, who was inspired by the title of the essay What is Art ? by Leo Tolstoy. Robbins did the same in the book Great Expectations : The Theory of Optimal Stopping he co-authored with Y. S. Chow and David Siegmund, where one can not miss the connection with the title of the novel Great Expectations by Charles Dickens.