US government profiles of countries and territories around the world prepared by the Central Intelligence Agency.  Includes information on geography, people, government, transportation, economy, communications, transportation, military and transnational issues.  A special section, Flags of the World, features color images of the countries' flags.  With the exception of the official seal of the CIA which may not be copied without permission, the Factbook is in the public domain and may be copied freely.

Millions of books and historical documents that have been scanned by Google.  Keyword searchable. Includes both copyrighted and public domain books.  Can be used as a resource for diagrams and illustration.  Note that only public domain, out-of-copyright books, can be downloaded.