Did you know that since October 2006, Google has partnered with the University of California to digitize collections from the UC LIbraries?
Go to http://books.google.com or from the Google homepage, under the more... link, select the Books option.
You can search a book's content and some may be available to download.
Find out more about Google Book Search. In addition to the UC libraries, Google Books collection provides access to materials from select libraries around the world through the Google Books Library Project.