The translator, Jean Rhys Bram, writes, "Magic, philosophy, science and theology combine in strange ways in the thinking of the last centuries of the Roman empire..... Firmicus seemed worthy of note for many reasons. He is almost alone as author of works produced both before and after an apparent conversion to Christianity.... He left a lengthy handbook detailing the astrological practices of his day, the only work which has come down to us in its entirety [90% Holden] out of numerous astrological treatises written in the Hellenistic and Roman periods..... This manual was important because it was the channel for astrological lore to the Middle Ages and Renaissance." (from the Preface) One of the finest of all ancient astrological texts, this is also one of the best-translated.
Julius Firmicus Maternus was one of the fathers of horoscopic Astrology. He explained in detail in the 4th century A.D. the Hellenistic Horoscopic System introduced by Claudious Ptolemy, Vetious Valens and other Greek Astronomers of the 1st century A.D. This book contains all sides and meanings of the Zodiac Signs, the planets, the system of the 12 houses and the aspects of the planets. Because of the abstract nature of the "Tetravivlos" of Claudious Ptolemy, "Mathseseos Libri" by Maternus is the full explanation of that theory which is also applied in our era.