I'm not sure if a Tom Ripley novel by Patricia Highsmith is forgotten, but they don't really seem to get the merit they deserve. The books are strangely appealing, even though there's a nihilistic streak to them. It seems to make the books more enticing, though.
In Ripley Under Water Ripley is suddenly threatened by a strange American couple, who seem to know something about Ripley's shady past and some killings he's done. Ripley of course wants to get rid of them, but there's also another reason: he thinks they are irritating, behave badly, disturbing the peace of the French countryside. It's entertaining that Ripley can consider murdering people only for behaving badly in public, not playing by the rules. Ripley only wants to spend time with his beautiful wife, play some music, do some amateur paintings of his own, eat the good food his maid prepares. In Highsmith's world, this can be sometimes achieved only through murder.
Ripley Under Water suffers somewhat from being too slow, especially in the middle when nothing much happens, but the ending is strong.
More Forgotten Books at Patti Abbott's blog here.
Edit: of course I meant "appealing", but this went as "strangely appalling" for many days. I noticed it, but couldn't do anything about it as I was travelling!