This book started out as bits of documentation written by René Rebe, which were then gradually updated and enhanced according to the changes and progress made in T2 as well as user and developer feedback. As such, it has always been under a free license. (See Appendix C, Copyright.) In fact, the book was written in the public eye, as a part of T2. This means two things:
You will always find the latest version of this book in the book's own Subversion repository.
You can distribute and make changes to this book however you wish—its under a free license. Of course, rather than distribute your own private version of this book, we'd much rather you send feedback and patches to the Subversion developer community.
A relatively recent online version of this book can be found at http://www.t2sde.org/documentation/.