Wikibooks

A project by the Wikimedia Foundation.

A collection of open-content textbooks that anyone can edit.


 * https://en.wikibooks.org/wiki/Main_Page (english)
 * https://de.wikibooks.org/wiki/Main_Page (german)
 * https://en.wikibooks.org/wiki/Wikibooks_portal (other languages)

Also see: List of largest wikibooks

Related: Wikimedia Foundation, Wikipedia, Project Gutenberg