Amazon takes down books whenever the publisher says to, but the book remains accessible from Manage Your Kindle and the Kindle Cloud. I know, because a friend has at least one book like that. And because I have checked out three or four OverDrive books that are otherwise nonexistent (deleted older editions, it seems).
There is that famous report about the *other* book -- the one Amazon remotely deleted and suchlike -- but since that was pulled for being illegal, it might have something to do with it. Or because that was the first ever case of an ebook vendor remotely deleting books, and they were very sorry about it (in both senses):
http://www.pcworld.com/article/17295...4_lawsuit.html
And afterward, they made a policy not to ever do that again
and I assume the other vendors took notes. (An odd idea that no one seems to believe in, hence the oddly widespread idea that only Amazon would ever do such a thing, simply because they are the only one to
have done such a thing.)