Possibly the oldest form of divination known, astrology assumes the physical world to be a reflection of the cosmos, "As above, So below." Astrology uses the relative positions and movements of the Sun, Moon, planets, and lunar nodes to come to a better understanding of human lives and of reality in the world.
Throughout history there have been many systems of astrological interpretation, including the Chaldean, Babylonian, Chinese, Hindus, Tibetan, Mayan, and, of course, the Greek. It is the Greek system that is used today in the West. It is largely based upon Ptolemy's book, known as the Tetrabiblios,
or the "Four Books on the Influence of the Stars". It is the Greeks that made it possible for astrology to become accessible to the European public.