Tom Tykwer, Andy Wachowski and Lana Wachowski are getting ready to turn David Mitchell‘s strange multi-narrative novel Cloud Atlas into a big-budget film. It will be shot entirely in and around Berlin, and is planned as the most expensive film ever to be financed in Germany, at about $100m.

The stellar cast includes Tom Hanks, Hugo Weaving, Ben Whishaw, Halle Berry, Susan Sarandon and Jim Broadbent, each of whom will play multiple roles — as many as six each. We have pretty good ideas about some of the roles each actor will play, but have wondered quite a bit about how the script deals with the fact that the novel features six stories that take place in different time periods. Now David Mitchell offers some very slight clarification — or, for those who’ve spent a lot of time thinking about the adaptation, possibly some confirmation of the planned strategy.

Mr. Mitchell tells The Guardian:

They aren’t attempting merely to film the book, which is why many adaptations come to grief – the novel’s already there, so why spend all that effort on an audiobook with visuals? Rather, the three directors have assembled Cloud Atlas and reassembled it in a form which – fingers crossed – will be a glorious, epic thing. The reincarnation motif in the book is just a hinted-at linking device, but the script gives it centre stage to link the six worlds with characters, causes and effects. A novel can’t do multi-role acting: a film can. The directors are playing to the strengths of their medium, just like I try to.

An adaptation that is free to play with the source material? Love it. And an author that endorses the approach? Even better! Right now, the idea is to shoot later this summer and release in October 2012, though that release date is hardly set in stone. Producer Stefan Arndt says Cloud Atlas will be “pure German film,” despite the fact that the dialogue will be in English.

Let’s recap info about the structure of the novel, to make clear why the film is a challenging adaptation:

Cloud Atlas is difficult to quickly summarize, as it is made up of six nested stories that take place in divergent locales and time periods and are written to emulate a variety of popular and literary styles. (Seafaring adventure, political thriller, dystopian sci-fi, post-apocalyptic fantasy, etc.) The first story is set in the mid-1800s, and the final one takes place hundreds of years in the future, when most civilization has been reduced to nothing.

The structure of the book is strange, too, and could be mapped out like so: 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1. You get the first half of the first story, which breaks off abruptly, then goes to the first half of the second, which references the first, and so forth until the sixth tale, which is presented in its entirety. Then the second half of the fifth tale takes place, and so forth until the novel ends with the completion of the first story.