From Pub Rants: http://pubrants.blogspot.com/2011/02...est-issue.html
Head / desk.In the new Macmillan contract is clause 6. (b) Copyright on Derivative Works. To state bluntly, this clause gives the Publisher the right to create “derivative works” based on the work they are buying from the author. And to add insult to injury, the publisher owns the copyright to any of these “new works.”
Yes, it is as bad as what you are thinking it means.
First, this is actually in direct contradiction to US copyright law and can’t be legally enforce but hey, what do I know.