The existence of neutron stars was not only a brilliant theoretical prediction, but also one of the most unexpected and astonishing discoveries of all heavenly bodies. Twenty-five years after the remarkable event of their discovery, neutron stars, which are the densest, the most strongly magnetized, and the most rapid ly rotating bodies in the Galaxy, remain objects of intense interest. This book is a revised and enlarged version of the original Russian edition. The last five years were marked by the discovery of a supernova in the closest galaxy and dozens of X-ray sources and millisecond...