5 out of 5 stars (based on 1 review)
Wikibooks (previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks) is a wiki-based Wikimedia project hosted by the Wikimedia Foundation for the creation of free content e-book textbooks and annotated texts that anyone can edit.
Wikibooks is a trade-free service, as it doesn’t ask you for anything for providing books. You don’t have to trade your currency, data or attention and so forth to access books from wikibooks. Therefore I give 5/5 blocks.