I finished Blood Meridian (1985) a few days ago, but I needed a few days to digest what I'd read before posting anything. The novel follows The Kid, a teenager from Tennessee who joins a group of outlaws in Mexico and helps them murder, rape, and steal their way across the countryside. McCarthy doesn't gloss over any of the nasty parts, either -- the violence in the book is graphic, unsettling, and abundant. Even so, I don't want to give the impression that the violence in the book is needlessly gratuitous. I mean, it is absolutely gratuitous, excessive even, but never needlessly so. Every last bit of it is central to the several themes of the novel.
On one level, Blood Meridian is a blunt de-mythologizing of the Wild West. Hollywood's cattle rustlers whose bullets never hit their target and strangely honorable duel-at-high-noon bad guys have been replaced with the actual wanted men, cavalry soldiers, and Indian warriors who terrified populaces across the West and Southwest in all their psychopathic, nigh-feral grotesqueness. Men are disemboweled and mutilated, babies are dashed against rocks, women are scalped and raped as they lay dying. It's damned tough to romanticize anything about this part of North American history after you understand the sorts of things that really went on back then.
The violence also serves as an exploration of the depravities in which humans are capable of indulging, and some of those explorations take the form of ad hoc discourses by Judge Holden, the outlaw gang's second in command and one of the most remarkably complex characters I've come across in recent memory (he's a sort of Death/Old Testament/Satan figure, among other things).
The dark subject matter makes the book uncomfortable to read in places, but hopefully that won't stop someone from reading it themselves. A large part of its impact on the reader lies in the stark power of its unflinching depictions of human cruelty, and the book absolutely deserves every bit of the praise that's been heaped upon it over the years. Just expect to come out of the experience a bit drained.