Duke de Richleau Adventure VI. What Dennis Wheatley did not know about both black and white magic wasn’t worth knowing.   the Duke de Richeleau and Rex Van Ryn know something bizarre has happened to their friend Simon Aron. Why else would he fail his most trusted friends?  The Duke has a suspicion, but nothing can prepare him or Van Ryn for the terrible confirmation of his fears.  Their oldest friend has fallen prey to the Forces of Darkness – through a powerful emissary of Satan against whom all earthly faculties are useless. Cover art by Herb Schmitz.