Readers of this book should be prepared to study. Yeats knowledge of mysticism is deep. He was a member of the Order of the Golden Dawn and had experience in conjuring in the British Museums with Assyrian artifacts. This book is based on a form of astrology, but not of the modern day "what's your sign " superficiality. Again readers must be prepared to do additional study, in the Vedas, the Gita, and Buddhist classics (start with DT Suzuki). This book ranks with Freud for its magnitude . Yeats has not been given the credit he deserves.