The unifying factor of this collection is that, without exception, every author included here was in some way or another involved with or interested in the occult. In some cases, they were members of an occult organization, such as the Hermetic Order of the Golden Dawn, the Theosophical Society or similar such groups. Others simply had a strong personal interest in the subject matter or practiced some form of the esoteric sciences in private, their interests having been preserved through diary entries and letters to their peers or documented by the publishing legacy they left behind. The co-mingling of fiction and non-fiction is very much how this written material would have been published at the time. Writers include Manly P. Hall, Aleister Crowley, Algernon Blackwood, Helena P. Blavatsky, Arthur Machen, Franz Hartmann, Lafcadio Hearn, Lord Dunsany, C. W. Leadbeater, William Q. Judge, H. W. Percival and Richard Garnett.