Library Lookup generates a bookmarklet for requesting a library book from a local branch based on the Amazon page you’re currently viewing. I went to my Amazon wishlist (books I might buy) and selected a book from the list.
When I arrived at the book’s detail page at Amazon, I clicked on the bookmarklet in my Firefox bookmarks toolbar, which generated a results page showing the book available at two separate library branches that are some distance from me. I called one of them to have a copy shuttled over to the library branch in my neighborhood. Sweet!