The Associated Press talked to Matt Stover, author of the 'Revenge of the Sith' novelization. Here's a clip:
Stover began writing the novel in the fall of 2003 and finished the following summer. Revisions were dictated both by the editing process, including a line-by-line review by Lucas, and by changes in the script itself.
"What you had was primarily alteration in the order of certain scenes," Stover says, "although in the beginning of the film, there were several events removed that I had spent a long time trying to shoe horn into the novel. But they were removed for a very good reason: They didn't fit."
Stover acknowledges that the novel gives away much of the film's story, but doesn't worry that fans will be satisfied by the book alone. He considers "Star Wars" a modern myth, less about a surprise plot twist than about the experience, shared with millions, of seeing a story told over and over.
Hit the link above to read more. Thanks to Mario for the alert.