There is no such law. If you own a book, you're free to lend it out, give it away, rent it, destroy it, slice it up and hang it on the wall, resell it, and so on. What you're not free to do is copy it. (That's why it's called "copyright".) There are a few other rights governed by copyright, like public performance of musical and dramatic works, preparation of derivative works, right of attribution, and so on. But lending is not one of them! (The key case establishing the principle is Bobbs-Merrill Co. v. Straus, 210 U.S. 339 (1908)). Public display is another right that travels with ownership of a copy. If you own a legal copy of a piece of art, you are allowed to hang it and let others look, or else museums would all be in trouble! (17 USC 109 (c))
The reason that things are different for DVD's is an anomaly arising from how digital media work. In order to play a DVD, the player has to copy the bits off the disk into its memory. This, the courts have held, is copying, so the owner of a copy actually has no right to play it other than the one granted by the license at time of purchase - which for consumer-grade DVD's is usually, "private showing within the home to family members and guests."
So feel free to donate books to libraries to your heart's content, irrespective of where they bought them. (That will often be Baker and Taylor, or McNaughton, simply because those outfits negotiate a pretty good price for quantity buys.)