Neptune (the planet)
Saturn, Uranus, Neptune and Pluto are the four slow-moving outer planets. When these planets shift from sign to sign, they indicate important changes in society. The type of change depends on the character of the sign.
Neptune is the planet of mysticism, spirituality and illumination. It is also the planet of chaos, confusion, delusion, deception, treachery and scandal. Neptune is associated with all methods of avoiding or escaping reality—the ultimate, of course, being drugs.
Neptune is therefore associated with drug and alcohol abuse and is one indicator of sexual perversion. It rules the ocean, liquids, swamps, drugs, medicines, gases and poisons. In the social sphere it rules democratic and popular movements, the common people, epidemics, social unrest and socialism. Neptune also governs the national taste for music and the arts.
We have seen that historically, when combined with Saturn, Neptune is related to the aggressive expansion of World Communism.
Neptune rules Pisces, the sign that on the positive side indicates liberation through ultimate self-sacrifice, and on the negative side indicates physical or psychological imprisonment due to self-delusion. Neptune rules matters that are often shrouded from public sight but that have physical consequences, such as drug abuse and the transmission of venereal diseases.
Sources
Pearls of Wisdom, vol. 33, no. 10, March 11, 1990.
Elizabeth Clare Prophet, The Astrology of the Four Horsemen, chapters 7, 19.