The book does not get removed from your bookshelf until both Boxers have accepted the Box-O-Books swap.
- If the swap is then canceled, both Boxers will need to repost those books to their bookshelves if they still have them and want to offer them again for swapping.
This feature of Box-O-Books was added at the request of Boxers who wanted to be able to consider multiple Box-O-Books swaps at the same time, as well as for-credit swaps, for books they have Posted to their bookshelf.
Related Links:
What is Box-O-Books?
Box-O-Books Tutorial