This edition reprints Volume 1 of an important two-volume Russian work which, at the time of its original publication, was the only comprehensive review in existence of the entire field of relativistic astrophysics. Subsequently revised and enlarged, both volumes remain today a valuable resource for physicists, astronomers, and others working in the field.The present volume is devoted to general relativity, properties of matter under astrophysical conditions, and stars and stellar systems. Individual topics include the theory of gravitation (including Einstein's gravitational equations), the equation of state of matter (cold matter, properties of matter at high temperatures, etc.) and relativistic stages of evolution of cosmic objects (equilibrium and stability of stars, stellar evolution, star clusters, more).The authors of this book rank among the great astrophysicists of the century: their work is especially remarkable for its deep physical insights and clarity of presentation. Those features are here in abundance, ready to inform and inspire both practicing astrophysicists and aspiring students.