This book contains a set of articles based on a session of the annual meeting of the American Association for the Advancement of Science held in San Francisco in February, 1974. The reason for the meeting arose from the need to communicate to the largest possible scientific community the dramatic advances which have been made in recent years in the understanding of collapsed objects: neutron stars and black holes. Thanks to an unprecedented resonance between X-ray, y-ray, radio and optical astronomy and important new theoretical developments in relativistic astro­ physics, a new deep understanding has been acquired of the physical processes oc­ curring in the late stages of evolution of stars. This knowledge may be one of the greatest conquests of man's understanding of nature in this century. This book aims to give an essential and up-to-date view in this field. The analysis of the physics and astrophysics of neutron stars and black holes is here attacked from both theoretical and experimental points of view. In the experimental field we range from the reviews and catalogues of galactic X-ray sources (R. Gursky and E. Schreier) and pulsars (E. Groth) to the observations of the optical counter­ part of X-ray sources (P. Boynton) to finally the recently discovered gamma-ray bursts (I. Strong) and pulse astronomy R. B. Partridge).

Supernovae.- Pulse Astronomy: Short Time Scale Phenomena in Electro¬magnetic and Gravitational Wave Astronomy.- Cosmic Gamma-Ray Bursts.- The Physics of Gravitationally Collapsed Objects.- Observational Properties of Pulsars.- The Galactic X-Ray Sources.- Optical Observations of Binary X-Ray Sources.- Black Holes and Neutron Stars: Evolution of Binary Systems.- Appendix I/Classic Papers.- S. Chandrasekhar / The Highly Collapsed Configuration of a Stellar Mass.- L. Landau / On the Theory of Stars.- W. Baade and F. Zwicky / Supernovae and Cosmic Rays.- J. R. Oppenheimer and G. M. Volkoff / On Massive Neutron Cores.- J. R. Oppenheimer and H. Snyder / On Continued Gravitational Collapse.- S. Chandrasekhar / Some Remarks on the State of Matter in the Interior of Stars.- J. Weber / Detection and Generation of Gravitational Waves.- Appendix II/Contemporary Papers Leading to the Discovery of Gravitation Ally Collapsed Stars.- R. Giacconi, H. Gursky, F. R. Paolini, and B. B. Rossi / Evidence for X-rays from Sources Outside the Solar System.- Ya. B. Zel'dovich / The Fate of a Star and the Evolution of Gravitational Energy upon Accretion.- I. S. Shklovskii / The Nature of the X-Ray Source Sco X-1.- A. Hewish, S. J. Bell, J. D. Pilkington, P. F. Scott, and R. A. Collins / Ob-servation of a Rapidly Pulsating Radio Source.- T. Gold / Rotating Neutron Stars as the Origin of the Pulsating Radio Sources.- R. Penrose / Gravitational Collapse: The Role of General Relativity.- R. Ruffini and J. A. Wheeler / Introducing the Black Hole.- V. F. Shvartsman / Halos around Black Holes.- N. I. Shakura / Disk Model of Gas Accretion on a Relativistic Star in a Close Binary System.- E. Schreier, R. Levinson, H. Gursky, E. Kellogg, H. Tananbaum, and R. Giacconi / Evidence for the Binary Nature ofCentarus X-3 from UHURU X-Ray Observations.- C. E. Rhoades, Jr. and R. Ruffini / Maximum Mass of a Neutron Star.- R. A. Hulse and J. H. Taylor / Discovery of a Pulsar in a Binary System.- Editor's Comment on the Binary Radio Pulsar.- Index of Subjects.