They'll probably accommodate you for the sake of good customer service.
However, relying on this constitutes an abuse of their good-faith customer-service intentions. If you'd wanted just to read the book, instead of owning it, then you should have gotten it at a library.
Originally posted by ElementZ
The company I work for allows this with minimal hassle. Granted we don't sell books but customers who order online can take merchandise back to the store. If they have no receipt, they have to show photo ID and only receive the store credit of the current price.
But books are a special case. With most products, people buy them in order to use them frequently, but with books and other media, people derive most of the value in the week following purchase (the first read-through.) That's why there is usually not a return policy on DVDs, software, and music CDs - if opened, you can usually only exchange it for another copy of the same item, and only if the first is demonstrably defective. Books are the same, so I would expect an official policy of not allowing returns on books.
- David Stein