book as obtained and not going into the copyright side of duplicating it etc. Copyright violation is a breach of the license agreed to with the purchase, and I left that out of the discussion as I was comparing what you can do with the two different media.
As to the removal of books, there has been a major case already, back in 2009
http://en.wikipedia.org/wiki/Amazon_Kindle#Remote_content_removalit was major news headlines and much discussion at the time.
Another aspect to look into is the special program Apple have created to help people write and create e-books. One of the terms of use for that is that once the book is created the book and content in that format belongs to Apple. not a nice way to do things.