Quoted from the author's "Preface."
"THREE Friars, says a legend, hid themselves near the Witch Sabbath orgies that they might count the devils; but the Chief of these, discovering the friars, said — `Reverend Brothers, our army is such that if all the Alps, their rocks and glaciers, were equally divided among us, none would have a pound 's weight.' This was in one Alpine valley. Any one who has caught but a glimpse of the world's Walpurgis Night, as revealed in Mythology and Folklore, must agree that this courteous devil did not overstate the case. Any attempt to catalogue the evil spectres which have haunted mankind were like trying to count the shadows cast upon the earth by the rising sun. This conviction has grown upon the author of this work at every step in his studies of the subject.
In 1859 I contributed, as one of the American `Tracts for the Times,' a pamphlet entitled 'The Natural History of the Devil.' Probably the chief value of that essay was to myself, and this in that its preparation had revealed to me how pregnant with interest and importance was the subject selected. Subsequent researches in the same direction, after I had come to reside in Europe, revealed how slight had been my conception of the vastness of the domain upon which that early venture was made. In 1872, while preparing a series of lectures for the Royal Institution on Demonology, it appeared to me that the best I could do was to print those lectures with some notes and additions; but after they were delivered there still remained with me unused the greater part of materials collected in many countries, and the phantasmal creatures which I had evoked would not permit me to rest from my labours until I had dealt with them more thoroughly.
The fable of Thor's attempt to drink up a small spring, and his failure because it was fed by the ocean, seems aimed at such efforts as mine. But there is another aspect of the case which has yielded me more encouragement. These phantom hosts, however unmanageable as to number, when closely examined, present comparatively few types; they coalesce by hundreds; from being at first overwhelmed by their multiplicity, the classifier finds himself at length beating bushes to start a new variety. Around some single form — the physiognomy, it may be, of Hunger or Disease, of Lust or Cruelty — ignorant imagination has broken up nature into innumerable bits which, like mirrors of various surface, reflect the same in endless sizes and distortions; but they vanish if that central fact be withdrawn.
In trying to conquer, as it were, these imaginary monsters, they have sometimes swarmed and gibbered around me in a mad comedy which travestied their tragic sway over those who believed in their reality. Gargoyles extended their grin over the finest architecture, cornices
coiled to serpents, the very words of speakers started out of their conventional sense into images that tripped my attention. Only as what I believed right solutions were given to their problems were my sphinxes laid; but through this psychological experience it appeared that when one was so laid his or her legion disappeared also. Long ago such phantasms ceased to haunt my nerves, because I discovered their unreality; I am now venturing to believe that their mythologic forms cease to haunt my studies, because I have found out their reality."