This is volume four of Martin's epic A Song of Ice and Fire. Don't try to start in the middle. It was perhaps a mistake for me to read Crows without re-reading A Game of Thrones, A Clash of Kings, and A Storm of Swords, because it's been so long since Swords came out, but I read too slowly and these are long books. If you haven't started reading the series yet, you may want to wait until it's actually finished, if you'd rather read a whole stack of 700 page books than sit around frustrated, waiting impatiently for the next one with the rest of us.
This book is definitely another chip off the same block as the earlier ones in the series. Martin's writing is so rich and compelling that he sucks you into his world completely, and it's a delight to read even as almost everything that happens is horrible. Psychopathic villains are fascinating. Stalwart heroes are brave and delightful, and usually come to horrible ends. As with the earlier volumes, Crows jumps between many viewpoint characters, advancing their stories significantly, but by the end of the book, the overall story hasn't advanced very far, and we're still waiting on the edge of our seats to see what happens next in each of a double handful of subplots -- not even counting the characters left hanging in earlier books that stay offstage in this volume. Westeros is still in the most interesting times imaginable, even a little more interesting than they were after the first three books; you really wouldn't want to live there (unless you're a crow), but for all the frustration and lack of conclusion, it's still a lot of fun to read, because chapter by chapter the story is told so damn well.
Maybe not quite as good as the earlier volumes, but if not it's certainly very close. Don't expect a conclusion, but if you're ready for more adventures along the way, don't wait. A Dance with Dragons is supposed to be along in another year -- and they're no longer billing it as the conclusion either, just a continuation. For all there is to be frustrated about, I still have to give this a 9 out of 10.