The Book of the Nine Judges is a famous medieval compendium of traditional horary astrology, compiled from Abu Ma'shar, Masha'allah, Sahl bin Bishr, 'Umar al-Tabari, al-Kindi, Abu 'Ali al-Khayyat, "Dorotheus, " "Aristotle, " and Jirjis. It is the largest known compendium of these sources on answering horary questions, and in many cases is the first modern translation of these Latin/Arabic authors. Complete with an introduction to questions by the translator, with numerous diagrams, tables, and an extensive glossary, it is essential for traditional astrologers.