This edition includes 250 alphabetically arranged articles on astronomy and astrophysics-most selected from the McGraw-Hill Encyclopedia of Science and Technology, Seventh Edition, with 30 written by leading authorities especially for this volume-and more than 400 illustrations, including 14 color plates. It covers the latest data, advances, discoveries, models, theories, and scientific methods, and provides quick access to every subject of classical and modern astronomy. An indispensable tool for scientists, students, librarians, science writers, serious amateur astronomers, and all others who need reliable, accurate, detailed, and up-to-date technical information on a wide variety of astronomical topics in a readily accessible format.