"This new, fourth edition of Allen's classic Astrophysical Quantities belongs on every astronomer's bookshelf. It has been thoroughly revised and brought up-to-date by a team of ninety internationally renowned astronomers and astrophysicists." "While it follows the basic format of the original, this reference has grown to more than twice the size of the earlier editions to accommodate the great strides made in astronomy and astrophysics."--BOOK JACKET.