G. H. Hardy was one of this century's finest mathematical thinkers, renowned among his contemporaries as a 'real mathematician. the purest of the pure'. This 'Apology', written in 1940, offers a brilliant and engaging account of mathematics as very much more than a science; when it was first published, Graham Greene hailed it alongside Henry James's notebooks as 'the best account of what it was like to be a creative artist'. One of the main themes of the book is the beauty that mathematics possesses, which Hardy compares to painting and poetry. For Hardy, the most beautiful mathematics was that which had no practical applications in the outside world (pure mathematics) and, particularly, his own special field of number theory