Worldcat is a comprehensive catalog of books and other materials held in libraries throughout the United States and even some international libraries. The Center for Research libraries' catalog contains more than 500,000 monographs in all formats and subject areas. Europeana searches European libraries, archives, museums, and galleries.
The resources listed here are not the only ones available. Many others are in print or microform and can be found by searching library catalogs, like CMU's library catalog, or Worldcat, a database of library holding thoughout the world (though mainly U. S.). Use some of these terms combined with your topic:
early works to 1800
women and diaries
slavery and "early works"