Can I just breath a sigh of relief that this is last year that's on my list of favorites for the Aughts, and by far the best book I've read for the Cannonball up to now.
Cloud Atlas is a collection of six vaguely inter-related novellas which are split into two pieces following the order A-B-C-D-E-F -F -E-D-C-B-A. Each of the novellas is set in a different time and is written in a different genre style. Each of the individual stories is compelling on its own, but its also interesting to see how each of stories is linked to the ones around it.
If you want to find out something about each of the individual stories, you can check out basically any review on Amazon, but one of the things I liked best about the book was the sensation of being plunged into chaos for the first few pages of each novella.
Without giving away too much, these novellas range from the diary of a man living during the British Empire to a mystery/thriller set in the 70s to the tale of an apocalyptic future.
This is a book that is considered serious literature, but it doesn't read like it -- the pages fly by and while it provides plenty of fodder for serious thinking, it's also possible to just read it for fun without getting hung up on the philosophical implications. It's a fairly long book, my copy is 538 pages, but since each individual section is only about 40 pages, it's also easy to read in a short time.
The only complaint I could make is that in the mystery/thriller section, Mitchell writes not like an excellent mystery writer but a second-tier one. I'm not even sure that this wasn't intentional -- given his talents, it's entirely possible that Mitchell wanted to sound like a hack in this section.
In any case, this book is fantastic.