The astrological poem (Carmen Astrologicum) of Dorotheus of Sidon (1st Century AD) played a key role in later Persian, Arabic, and Latin astrology, forming the basis of many works on nativities, inceptions or elections, and questions ("horary"), such as the Book of Aristotle, al-Rij¿l's Book of the Skilled, and the books of Sahl b. Bishr. After being translated into Persian in the 3rd Century, it was later put into an Arabic edition by the famous astrologer 'Umar al-Tabar¿. This new English translation of al-Tabar¿ explains many special features of Dorotheus's work, including chart dating, the use of triplicity lords, transits and profections, ascensional times, and more. With numerous footnotes, extra diagrams, and the Greek prose Excerpts (translated by Eduardo Gramaglia), it supersedes the 1976 edition by Pingree. This essential work for traditional astrologers and will repay close study. This updated 2nd edition (2019) replaces the 1st edition (2017).