This innovative reference work presents the concepts of modern astronomy and cosmology in terms that are uniquely informative and accessible. Through its clear, concise test, dramatic illustrations, and easy-to-use format, the book discusses the discoveries that have led to giant strides in our understanding of the universe, its origin, evolution, and eventual fate. This exciting story is one of amazing technical advances, including new super-computer modeling approaches and the Hubble Space Telescope, that are permitting scientists to probe deeper than ever into the mysteries of space, witnessing events and phenomena close to the beginning of time itself. The book begins with the even more startling story of the connection between astronomy and particle physics, and how scientists have learned much about the universe by studying the laws and behavior of the subatomic realm. The second section discusses the Big Bang theory, the beginning of time, the creation of matter, and the expanding universe. The following sections examine the nature of galaxies, quasars, and the myriad varieties of stars, including neutron stars and black holes, the most bizarre enigma in nature. The volume concludes with a discussion of the perplexing problem of the missing mass and the search for dark matter, with a look at what the future holds for interstellar travel and the possibility of finding life outside our solar system. This thematic presentation is supported by a 400-entry keyword section, in which all terms and concepts are clearly and simply explained, and a factfile at the end of the book that offers essential reference material on stellar astronomy and astrophysics.