The Polish philosopher and Marxist revisionist who critically examined positivism in The Alienation of Reason (1968) now discourses on God, man and the devil in an acidulous, playful fashion. In his conversations with the Devil Satan appears as a consummate dialectician with no charm whatsoever and little interest in miracles. Among the personae: Saint Peter, Orpheus, Luther ""inside God's bastion,"" and even Heloise singing her own hymn: ""Empty are Thy Paths/ My happiness is good and short and sinful!"" In The Keys of Heaven there are seventeen Biblical tales retold with ironic wit and hortatory ""morals"" of dubious morality -- for example Moral Two, deduced from""Esau, or the Relation of Philosophy to Trade"" will teach that ""Much profit can be derived from a minor alteration of the past."" Cognoscenti may appreciate the philosophical and theological paradoxes and reverses which are cunning and manipulative -- adventurous amateurs the witty exploitation of orthodox heresies.