Undisputedly one of the best books I've ever read (and I mean all books, not just CB's).
While I am not a huge admirer of Barker's mainstream fiction, and am rather sceptical of the whole horror stratum of literature in general, this is definitely a must read. I'd like to be useful, though, and so I think there's something you should learn outright: If you're in primarily for horror, if you're looking for gore, ripped flesh and other more sickly things; in other words, if you only like concrete colours and not shades, this book isn't for you.
For Sacrament is indeed a book written in shades. Above all, Barker is in my opinion one of the most talented stylists of our age. His narratives, even where they lack action and are simply contemplative, are plainly above praise. The enigmatic Jacob Steep and Rosa McGee who imbued the life of wretched Will Rabjohns with that uneasiness which was later to grow and wreck his sanity are probably among the most extraordinary, nontrivial, and so--on some very deep, rudimentary level--the most frightening characters I've ever encountered in the literature. To reiterate though, this is not the kind of fright you'd expect when you read about someone with a meat-ax about to crack your skull in two.
The book starts with Will Rabjohns, arguably the world's most famous wildlife photographer, trying to talk to a half-mad hermit who tucked himself away in a small northern village, Baltazar, about a mysterious couple he had met earlier in his life--Jacob Steep and Rosa McGee. So, in the first part of the book, we get a glimpse of Will Rabjohns the grown-up. Then, after an assault by a wounded bear, Rabjohns falls into a coma from which he may never recover.
His mind, meanwhile, drifts away to the recollections of how he grew up as a second and apparently much less loved child; in a family where his elder brother was ran down by a car and so killed. To save his mother shattered with grief, his father--a philosopher of some renown--decides to move to a village rather far from where they lived (Manchester), Burnt Yarley. There the plot starts to unfold in all its creamy and seductive magnificence.
Will makes friends (kind of) with a strange couple, a brother and a sister; and, as he's evidently not very welcome at home, he at a certain point in his wanderings simply gets lost in the fields during a storm. There, he meets another couple: a woman of unearthly beauty and her companion, a remarkably effective gentleman of some forty years. The couple and Will become friends, too... in a sense. Until, in the course of many strange events, he begins to uncover something about them (such as the fact that they are seemingly quite immortal, or that Jacob Steep seeks to cleanse the world of all the last species so that it may be cleaner and God's voice might be heard) which, were he adult, would make him flee them instantly--but since he's a boy, his psyche is flexible and so, as a flesh of a clam, adapts to a burning alien particle.
However as time goes, the pearl expands and devours him from the inside. Thus follows his awakening and the beginning of his conscious quest for Jacob Steep, the Killer of Last Things, and his fair lady Rosa McGee. The two men are intertwined (in a rather Freudian way, one might add) in a manner which none of them likes. It is a conflict which shall ultimately be resolved (with the addition of numerous other characters, all of them unlike anything you've seen before) and its resolution is the punchline of the book.
This punchline is very deep, unexpected, and moving. It seems as though the writer himself elected, in the end, to provide a bright and explicit summary of what it means to be wholly human... And so the notorious sexual aspect seems to be rather exaggerated. Yes indeed, the love scenes are depicted with some frankness (which I'm sure most erotomaniacs would brand as insufficient were it a usual love story), but they are by no means key in the book.
Finally, read the book if you love England. It is full of the kind of characteristically British (or so methinks) ennui, inset in an ornament of landscapes and weather crafted so meticulously and with such great love and care that The One Task of any Writer (you know, the one that rules them all)--to immerse you completely into the mood of the book--is fulfilled.
All in all, the book is much like a photoalbum where intricate sepia pictures are bound together by a no less meaningful fabric. It hints so delicately and yet so masterfully at the fact that there is something beyond that, if one ever doubted whether to place Barker together with the best writers of our day, these doubts now should wither and pass away.