In this book Mloninlow describes the history of geometry and its relation to other branches of science. The book progresses via the stories of five main characters, starting with Euclid and his 'Elements', then showing how Descartes linked geometry and algebra. It then looks at how Gauss initiated work on noneuclidean geometries, and shows how Einstein used this in the development of general relativity. The last part of the book concerns string theory and its development by Ed Witten. Mlodinow maintains his sense of humour throughout giving a very readable book, which is understandable by the non-technical reader.
Although the book has five main characters, it is not restricted to these people, rather it gives a history of much of geometry, in particular the development and use of noneuclidean geometries. Mlodinow explains the geometrical concepts as required, and does so very well. Sometimes I felt that another diagram would have helped the reader, but maybe this would have changed the book from one on the history of geometry to trying to teach the reader geometry, which would have changed the style of the book.