Now, Black Magic in the past may have been imposture reinforced by delusion, and to state that it is recurring at the present day does not commit anyone to an opinion upon its veridical origin.

To say, also, that the existence of modern diabolism has passed from the region of rumour into that of exhaustive and detailed statement, is to record a matter of fact, and I must add that the evidence in hand, whatever its ultimate value, can be regarded lightly by those only who are unacquainted with its extent and character.

This evidence is, broadly, of three kinds:--( a) The testimony of independent men of letters, who would seem to have come in contact therewith; (b) the testimony volunteered by former initiates of such secret associations as are dedicated to a _cultus diabolicus_; (c) the testimony of certain writers, claiming special sources of information, and defending some affected interests of the Roman Catholic Church.
My purpose in this book is to distinguish, so far as may be possible, what is true from what is false in the evidence, and I have undertaken the task, firstly, because modern mystics are accused, _en masse_, of being concerned in this cultus; secondly, because the existence of modern Satanism has given opportunity to a conspiracy of falsehood which is wide in its ramifications, and serious on account of its source; thirdly, because the question itself has awakened considerable interest both within and without transcendental circles, and it is desirable to replace hazy and exaggerated notions by a clear and formal statement.
I have connected the new diabolism with France in my title, because the evidence in each of its kinds has been filed by French writers, and we have no other source of information.

So far as that evidence is sound, we have to thank France for producing it; but, on the other hand, should it prove that a whole city of invention has been constructed, "with all its spires and gateways," upon a meagre basis of fact, it is just that French imagination should have full credit for the decorative art which has adorned this Question of Lucifer.
The plan of my work had been sketched, and a number of chapters written, when I found myself to some extent preceded by a writer well known to occultists under the pseudonym of Papus, who has quite recently published a small brochure, entitled _Le Diable et L'Occultisme_, which is a brief defence of transcendentalists against the accusations in connection with Satanism.

I gladly yield to M.Papus the priority in time, which was possible to a well-informed gentleman, at the centre of the conspiracy.