I think my git book in Croatian (LaTeX source here) can be now considered "finished". It started from a short document with the most basic git commands to help friends moving to git (from SVN and TFS). But as they kept asking me questions I was adding more and more content to the document. After a few months it had more than 60 pages of text, so I decided to make it a real book. It is now more than 150 pages, and it is (AFAIK) the only git introduction book in Croatian (and Bosnian and Serbian, since our languages are more like dialects than real languages).
The book is open source (Creative Commons Attribution-ShareAlike 3.0), and after more than 3 years from the initial commit more than 20 people helped me with patches and suggestions. Thank you all!