The Blue Equinox details the principles and aims of the secret society O.T.O. (Ordo Templi Orientis) and its ally the A?A?, both of which were under Aleister Crowley's control at the time book was published. It includes such topics as The Law of Liberty, The Gnostic Mass, and Crowley's "Hymn to Pan". The book opens with Crowley's poem "Hymn to Pan", a devotional work devoted to the ancient Greek deity Pan. This is followed by an editorial, in which Crowley discusses Thelema, the A?A? and the O.T.O., and the important role which he believed that they had to play in the Aeon of Horus.