Now in paperback, this book by Nobel prizewinner S. Chandrasekhar, is devoted to the mathematical theory of the space-times surrounding the black holes of nature. Since the general theory of relativity provides a single unique family of solutions (the Kerr family) for black holes, the subject is mathematically a very well defined one. Besides, the analysis discloses a richness rarely encountered in mathematical physics. A preliminary chapter provides the basic mathematical tools. The principal chapters deal with the Schwarzchild solution describing static spherically symmetric black holes. The geometry of these space-times is analysed in terms of their geodesics. A particular feature of the book is the collection of illustrations exhibiting the various classes of geodesics.