To be sure, though, there is something enigmatic about Trevor, some inscrutably dark center of his being. But Trevor himself is quite definitely not evil incarnate. The student of Greene's fiction knows the strong proclivity of the author for the saint-sinner paradox—his Manichean-like belief that good and evil are the opposed forces in the universe but that they everywhere interpenetrate in this post-lapsarian world in ways which are endlessly confusing. Evil can be found in good men, and often great good in men whom the world calls evil. A recurrent paradox in Greene's fiction (regarded by some as heretical and by others as simply sentimental) involves the notion that the man strongly attracted toward evil, or even wholly given over to it, is more apt to find the path to salvation than the faceless entity who remains forever morally uncommitted. Greene is of course not...