ANSWER: Theory of Anarchy

No Gods No Masters Vols.1 & 2. Guerin, Daniel. AK Press: April 1997 (both volumes). ISBNs: Vol.1 #1873176643, Vol.2 #1873176694
According to Powell's, this is the first English translation of Guerin's seminal work on the history and practice of anarchism in the West. It includes many unpublished letters and essays from founders and leaders in the movement. Appears to be a very broad, thorough reference.

Community, Anarchy, and Liberty. Taylor, Michael. Cambridge University Press: October 1982. ISBN: #0521270146
According to Powell's, this is a treatise on "a viable and stable form of an anarchic or stateless society." Author examines modern communitarian societies in his effort to advance the argument for the whole of civilization.

Encyclopedia of Political Anarchy. Kathryn and Martin Gray. ABC-CLIO, Inc.: May 1999. ISBN: #0874369827
This might be a bit too "101" for you, but it might also make an interesting resource for educating non-anarchists. It covers the history of all the various anarchist movements throughout the world up to and including such movements as the Zapatistas.

Finally, a website: Anarchy Archives: An Online Research Center for the History and Theory of Anarchism. Provides a wealth of information on historical and modern anarchism, publications, and other resources.