Astrologers and astronomers searching for the Star of Bethlehem have long overlooked this primary source for an important piece of evidence: Aries the Ram ruled over Judea. This helped me reveal the Star that pointed the Magi to Judea where the King of the Jews was born on April 17, 6 BC - two years before King Herod died. My book, The Star of Bethlehem: The Legacy of the Magi also made use of other astrological primary sources which showed that to understand the Magi's Star, we need to understand astrology as it practiced as Ptolemy described.
The Tetrabiblos belongs on every classical historian's bookshelf. It is a major primary source on astrology as it was praticed in Roman times.
The wonderful thing about this translation of Ptolemy's seminal work in Astrology is the conscientious and painstaking work to adhere to the original text which appears on the opposing side of the english text translation. I am in a position to corroborate myself its accuracy. As a result however the English text is not an easy or flowing contemporary style. This is not a quick read, and probably should be used as reference. It covers a multitude of Astrological areas and can serve as a springboard to further inquiry. The book is a compact size, typeface and spacing pleasant and non-fatiguing.