Abu Ma`shar [Ja`far ibn Muhammad ibn `Umar al-Balkhi, Abu Mashar, Abu Massar, Latin. Albumasar, Apomasar, Apomasor] (August 10, 787 AD, Balkh, Khorasan - March 9, 886 AD, Wasit, Iraq) - one of the most famous and authoritative medieval Arab astrologers, who played a large role in the formation of astrology. "A Great Introduction to the Science of the Judgments of the Stars" by Abu Ma'shara is one of the main sources on traditional astrology for more than a thousand years. Both medieval Arab astrologers, for example, Biruni, and many European authors based their works on it. In the "Brief Introduction", written in 849-50 AD, Abu Ma'shar left only specific elements of the system, excluding all philosophical reasoning and commentary. This is a reference book that gives a clear and systematic idea of the apparatus and methods of astrology at the end of the first millennium AD - the time of its greatest flowering. The text offered to your attention is a compilation translation based on the English edition of 1994 (series “Islamic Philosophy, Theology and Science”, vol. XV), verified with the Arabic original, the Latin translation of Adelyard of Bath (first half of the 12th century) and the corresponding chapters of the Arabic and Latin texts of the “Great Introduction”.