Ptolemy's Tetrabiblos : The Foundation of Western Astrology The (Greek for "Four Books"), often referred to by its Latin title Quadripartite , is a seminal work on the philosophy and practice of astrology written by the 2nd-century Alexandrian scholar Claudius Ptolemy . While Ptolemy is perhaps more famous for the Almagest , which provided the mathematical foundation for astronomy, he intended the Tetrabiblos to be its logical companion. Together, they formed a complete system: the Almagest explained the movement of celestial bodies, and the Tetrabiblos explained their supposed influence on the world. The Structure of the "Four Books"
: Ptolemy defends astrology as a legitimate, though less certain, science compared to astronomy. He introduces the "powers" of the planets based on physical qualities—such as heat, moisture, dryness, and cold—and describes the nature of the zodiac signs. Ptolemy's Tetrabiblos, Or Quadripartite
: The final book examines external life events, such as wealth, social status, marriage , and travel. Scientific and Philosophical Approach Ptolemy's Tetrabiblos : The Foundation of Western Astrology