Copyright is what it says. "The right to copy." A library does not violate copyright with either books or recordings as long as they are lending a legal publishing and not a copy. Beyond copyright what you buy is usually yours to do with as you please, but some publishing companies may try to impose license agreements between them and the buyer. This has been tried by the industry with very limited success. If you take anything home and copy it you are probably in violation of copyright.
That being said the publishing and music industries have pressured governments (with some success) to change the common law definition to their favor in some jurisdictions.