Free Online Resource

Interface searches a number of online digital libraries, digitized archive collections, and other resources whose internal contents are inaccessible to normal search engines. (Source: WorldCat)
The Online Books Page
John Mark Ockerbloom presents an index to full-text versions of works of literature, searchable by authors, titles, subjects, and serials. Users may browse the complete list of authors listed in the index. English literary works, as well as English translations of literary works in other languages, are available as part of the Online Books project. (Source: WorldCat)
Project Gutenberg
Project Gutenberg is another site that provides numerous books online. You can find books either by title or by author.
The Perseus Digital Library
Perseus is an evolving digital library, engineering interactions through time, space, and language. Our primary goal is to bring a wide range of source materials to as large an audience as possible. We anticipate that greater accessibility to the sources for the study of the humanities will strengthen the quality of questions, lead to new avenues of research, and connect more people through the connection of ideas. (Source: website)