Tetrabiblos In this treatise by the preeminent ancient astronomer, knowledge of the movement of the sun, moon, stars, and planets (studied in Ptolemy's Almagest) is put to practical use: making predictions about individuals' lives and the outcome of human affairs. Tetrabiblos first examines the "possibility and usefulness of such prognostication" and then offers detailed instruction on the subject. Ptolemy's manual, written in the mid 2nd century, is a core text in the history of astrology. Series No. 435 / 502 pages / ISBN 0-674-99479-5