The Key to Theosophy Author:H. P. Blavatsky This edition of H.P.B.?s ?Key to Theosophy? is a reproduction of the 1889 first edition. The Key to Theosophy outlines the central ideas behind the modern theosophical movement and the Theosophical Society. It is written in a way to be accessible to anyone, from first-time to long-time students of theosophy.