Ideas of Good and Evil by W. B. Yeats

From the Excerpts of the Book: I believe in the practice and philosophy of what we have agreed to call magic, in what I must call the evocation of spirits, though I do not know what they are, in the power of creating magical illusions, in the visions of truth in the depths of the mind when the eyes are closed; and I believe in three doctrines, which have, as I think, been handed down from early times, and been the foundations of nearly all magical practices.

William Butler Yeats was an Irish poet and one of the foremost figures of 20th-century literature. A pillar of both the Irish and British literary establishments, he helped the foundation of the Abbey Theatre, and in his later years served as an Irish Senator for two terms and was a driving force behind the Irish Literary Revival along with Lady Gregory, Edward Martyn and others.