The ancient doctrine of the Arabic Parts (or "lots") gives the astrologer a profound insight into the inner workings of a horoscope - whether it be natal, mundane, horary or electional. They are arithmetically derived points on the ecliptic which deal with all areas of life -including war, wisdom, commodity speculation, profession, marriage, children, partnerships, death and spirituality.

Until more recent times they have been largely lost to the modern astrologer. But those who have developed a competence in their use find them an invaluable key to delineation and accurate prediction.

The author, Guido Bonatti a thirteenth century professional astrologer, drew upon material produced by outstanding Arabic and Greek antecedents. He adds to their insight his own extensive experience. Used in conjunction with a thorough understanding of the astrological horoscope these Arabic Parts provide the serious astrologer with a profundity of insight otherwise not available.

The translation presented here is the only one available to the English reading public. It deals with that section of Bonatti's famous summa of medieval astrology the Liber Astronomia which unfolds this arcane doctrine. The translator Robert Zoller is a professional astrologer with thirty years experience in the field of medieval astrology.