This book contains translations of five astrological treatises by Medieval astrologers: Albumasar: The Book of Flowers, an anthology of rules for Mundane Astrology; Ptolemy: The Centiloquy; Hermes Trismegistus: The Centiloquy; Bethen: The Centiloquy; Almansor: The One Hundred and Fifty Propositions. This is the first comprehensive publication of these treatises, which were translated by James Herschel Holden, Research Director of the American Federation of Astrologers. He is especially interested in Classical and Medieval astrological works.