It's a good day for book-lovers so far... This Google development is fascinating, especially for people who have read The Long Tail (which includes, among many other topics, analysis of traditional and digital book distribution models).
Today, we're launching the Library Catalog Search feature in Google Book Search, designed to help casual readers and bookworms everywhere find gems in the libraries around the world. Queries on Google Book Search will automatically include results from library catalogs when appropriate. Each result includes a "Find Libraries" link to help readers find libraries that hold the book -- ideally a library nearby, or if need be, a library far away. For example, after reading Martin Gardner's book Fads and Fallacies, I wanted to follow up on Immanuel Velikovsky's books about scientific explanations for biblical miracles. Clicking on the "Find Libraries" link for Velikovsky's Worlds in Collision, I found that a copy was available in the University of Sao Paulo library.