Google Books
In Google Books you search for e-books that are scanned from a number of American, British and Spanish university libraries, or e-books from a great number of commercial publishers. Older books that are out of copyright are available in their entirety as full text, whereas most books are only accessible as excerpts.
Books in public domain are downloadable as PDF or ePub files.
Please note that you cannot search for the books in Google Books via Primo.