A short story, more than a novel. A novella, I suppose. Much is inferred and hinted at, though the story is quite simple: rich, successful and cultured man called Gustav von Aschenbach goes to Venice during the Belle Epoque on a bit of a whim and fancies the pants off a young adolescent boy. The ending is in the title, of course.
It quite brilliantly creates a mood of decay and decadence, without ever expressing it or describing it directly. A book to read slowly and savour.