Reviewsf: an ''alternate history'' novel, though marketed as a ''bestseller category'' novel.
the ''if hitler had won'' subgenre may be as large as that of the more strictly merkin subgenre ''if the south had won''; both groups are certainly larger than that of the ''if the grand / spanish armada had won'' novels.
sfaik the earliest ''if hitler had won'' novel is ''swastika night'' by katharine burdekin (1937), q.v. - originally published as by ''murray constantine''. other rightly famous examples include ''the sound of his horn'' by john w. wall, writing as ''sarban'' (1952), q.v., and ''the man in the high castle'' by philip k. dick (1962), q.v.