This beautiful little book is certainly suitable for anyone who has had an introductory course in physics and even for some who have not. Moreover, it contains enough substance so that a modern physicist may find that he can learn something--perhaps only that a difficult topic can be presented to a general audience. The whole succeeds so well because Geroch believes that 'physics is a human activity...' and wants to share some of its joys with others. - Joshua N. Goldberg, Physics Today.
