This is a very misunderstood work.
Michael McDowell was a brilliant author: "Guilded Needles" and "Elementals" are both outstanding novels in their respective genres. TOPLIN, however, is something quite different -- and most readers just don't get it, and walk away disappointed.
From reading the reviews, I'd assumed that TOPLIN was the story of a delusional psychotic who murders a waitress based solely upon a halucinatory vision only he can see . . . this is untrue.
TOPLIN may qualify as "psychological horror" -- if you need to pidgeonhole it into a set genre -- but it's really more of an experimental novel than anything remotely mainstream. The text is heavy on symbolism, allegory, and metaphor -- not all of which is immediately obvious (hence the confusion of others). Toplin is not necessarilly psychotic -- although he'd certainly be classified as such under the DSM-IV -- but he perceives trhe world with startling clarity. By definition, a delusion is something false, which is not at all the case in this deeply disturbing tale.
It is best to think of TOPLIN as a modernized retelling of the "Fool's quest," as the characterizatrions borderline on mythological, and the tone is downright Lovecraftian.
Highly recommended for fans of Thomas Ligotti, H.P. Lovecraft, or the Chtulhu mythos.