Cloud Atlas: A Novel is a great deal of fun. I’d not read or heard about David Mitchell until the film release was universally panned; film reviews made the book sound so interesting that I picked it up immediately.
The book is a series of narratives nestled inside one another like Russian dolls (the image occurs naturally to the reader as you move forward, but Mitchell makes it explicit at one point). You start in a 19th century Mellvillean sea story, and then move forward to 1930s Europe, and thence again and again. The language, the style, the context, the concerns of the characters–everything shifts appropriate to the temporal setting. Finding the clues which connect the narratives into a grand scheme makes it an even more entertaining and rewarding experience.
So there are several genres here: historical novel, political thriller, corporate espionage potboiler, science fiction, speculative fiction, picaresque–and all are clever, inventive, wholly realized, and satisfying. I didn’t find the structure a contrivance or a chore at all. I think Cloud Atlas is fine writing and has things to say about there are ramifications for the direction of our current global civilization. Its speculative or sci-fi aspects are as deep as Atwood’s or Ishiguro’s attempts in a similar vein, and as entertaining as anything by LeGuin or Jack Vance.