I can recommend the [Art of Community](http://www.artofcommunityonline.org/) as an authoritative reference work. The book is written by Jono Bacon,  previously Github and currently Ubuntu's Community Manager at Canonical. 

The book is even useful for people with limited background in interacting with online communities: It starts from the very beginning telling the reader the social and anthropological elements that bring a community together.

The book includes a *Community Case Book* showcasing interviews with some of the most important community builders like Linus Trovalds (Linux), Mary Colvig (Mozilla) just to name a few. Besides, the author shares his own experience in building the communities he's managed on his career. 

I found it very useful in being a community builder: It presented a framework to be followed, cleared a lot of misconceptions that I had and put in words things that I sensed but had not enough evidence to conclude what was fact. 


  [1]: http://www.artofcommunityonline.org/about/