[Wikibooks](http://wikibooks.org) and [Wikiversity](http://wikiversity.org) host textbooks and lectures, respectively, licensed under Creative Commons Attribution-ShareAlike.

They are hosted by Wikimedia Foundation, the same non-profit that hosts Wikipedia and other [sister projects](http://en.wikipedia.org/wiki/Wikipedia:Sister_projects).

Books and lectures can be downloaded in printed form or [ordered online](http://en.wikipedia.org/wiki/Help:Books/Printed_books) from PediaPress (which WMF has a partnership with) or a third party.