a contract clause is not always an obligation, it has to /can be negotiated

Recently, Simon & Schuster US changed a clause in its standard contract. By tradition, it was understood that once a book was out of print, the author could ask his publisher to have its right reverted, so that he can sell it to another publisher.
This is a legal obligation in France where the French Intellectual Property Code organizes very strictly that in such cases rights are automatically reverted to the author.

By a new clause, Simon & Schuster decided that as long as a reader could order a book by print-on-demand, it was not considered out-of-print. As a consequence, it will be highly difficult for an author to get his right back.
Up to now, they seem to be the only publisher to propose such a clause.
Nevertheless, one do not forget that a contract is the fruit of a negotiation and this kind of clause can be refused.

cf  New York Times 18th May 2007
cf The Guardian book blog (post by Nocholas Clee)