High marks for Asimov as he leads us down the astronomical garden path from particles and forces to black holes--the ultimate be-all or end-all of a collapsing (but maybe not) universe. The path is logically traced through the composition of planets and the evolution of stars through red giants and white and black dwarfs. From here we go to explore the more recent exotic flora--neutron stars, pulsars, quasars. Finally the gate is open to the world of the black holes, consisting of a mass so compressed by gravitational force as to overcome nuclear forces and escape velocity so that photons cannot radiate out (hence the hole's blackness). Then it's on to speculations that bespeak Asimov the sci-fier no less than the expositor as he discusses mini- or maxi-holes, "wormholes," white holes, and so forth. There are typical Asimov homely touches (he explains major concepts in terms of books on tables or earth-moon relations); there are dashes of ego and such idiosyncrasies as giving full names, dates, and national origins of scientists mentioned. These familiar trademarks can be attributed to that zeal which says "I know and want to explain." Certainly this is a good exemplification, exuberant and really quite exciting as it demystifies those longish all-too-often incomprehensible newspaper accounts.