“The book’s title is a reference to the Cloud Atlas Sextet, written by a fictional, young 1930s composer named Robert Frobisher, the protagonist of one of six loosely connected narratives that make up the novel.” In the book, author David Mitchell describes the piece in some detail – but director Tom Tykwer (himself a msuician) and his colleagues couldn’t both follow the description and make the music “satisfying for the film.”