There are a number of open access and free ebook collections available online. Most provide limited views and some full-text content, usually books in the public domain.
Previews and full-text of books. Full-text books are going to be books that are out of copyright, or books in which Google received permission from the publisher to reproduce.
HathiTrust is a partnership of major research institutions and libraries. The Digital Library is a repository providing access services for public domain and in copyright content from a variety of sources, including Google, the Internet Archive, Microsoft, and in-house partner institution initiatives.
Primarily a large book catalog, it is a project of the Internet Archive. The interface connects you to scanned versions of books from the Internet Archive and connects you to other places to find the books in print.
