Currently Being ModeratedJun 6, 2013 5:26 AM (in response to J__R)
Afaik, not without a back-up of your Library from before you accepted the irrevocable change. If you have the back-up, you should be able to restore the Library in that state, and finish the Book. You might be able to export the Book Album and import it into your regular Library. Do you have a back-up of your Library in the state it was in before you clicked "OK"?
The safe way to proceed when confronted with the kind of warning you got is to not continue, create a copy of the item being worked on (e.g.: duplicate the Book Album), and then move forward with one of the copies.