The world's largest book database, WorldCat serves as a shared library catalog for 25,000+ libraries worldwide. Contains links to books, periodical titles, videos, internet resources, and other cataloged resources in libraries. It also contains selected collections of periodical articles. Access from on campus or off campus, with no ID required.
This site provides access to electronic books from many of the most important web e-book collections. The great value in this smaller selective site is that it includes texts from a wide range of digitization projects. Access is free but very brief registration is required.
HathiTrust Digital Library is a digital preservation repository that provides long-term access for public domain and in copyright content from a variety of sources, including Google, the Internet Archive, Microsoft, and in-house partner institution initiatives.