Oxford Scholarship Online at City College Libraries offers access to the full text of over 1000 Oxford books in the disciplines of Economics and Finance, History, Philosophy, Political Science, Psychology, and Religion. Titles supported are marked with the clickable 'FULL TEXT' button.
WorldCat provides complete bibliographic information on nearly all materials published in all subject areas in all languages. It draws its information from the library holdings of thousands of libraries around the world. Included in the database are books, periodicals (but not individual articles), sound and video recordings, electronic resources, dissertations and theses.
This site, in German, provides an index to all the German language e-books freely available through Project Gutenberg. It offers an index by author. There is a bit of advertising.