This book started out as bits of documentation written by Subversion project developers, which were then coalesced into a single work and rewritten. As such, it has always been under a free license. (See Appendix D, Copyright.) In fact, the book was written in the public eye, as a part of Subversion. 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—it's 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. See the section called “Contributing to Subversion” to learn about joining this community.
A relatively recent online version of this book can be found at http://svnbook.red-bean.com.