This collection of papers is a comprehensive summary of progress made during the past decade on the theory of black holes and relativistic stars. The book is based on a Symposium on Black Holes and Relativistic Stars which was held on the University of Chicago campus on the weekend of December 14 and 15, 1996. The symposium was dedicated to the memory of Subrahmanyan Chandrasekhar, who died in August 1995. Chandra had devoted most of the last thirty years of his extraordinary scientific career to research on the theory of black holes and relativistic stars. This volume, which is based upon this symposium, also is dedicated to his memory.