https://en.wikipedia.org/wiki/Theosophy
Walter took an early interest in the books on spiritualism in his father’s library, reading as a teen both Isis Unveiled and The Secret Doctrine by Madame Blavatsky of the Theosophical Society. These works were to have a profound effect on Walter Wentz. Indeed, it is impossible to appreciate his tetralogy without recognizing his lifelong commitment to Theosophy. （in THE TIBETAN BOOK OF THE GREAT LIBERATION, Foreword, by Donald Lopez)
