"An excellent source of information regarding Anarchist (libertarian socialist) theory and practice. It covers all major topics, from the basics of Anarchism to very specific discussions of politics, social organization, and economics." -- Debian listing

An open project, licensed under the GPL, being written by Anarchists around the globe. Incredibly comprehensive, yet entirely navigable and readable.

It can be found online at http://www.geocities.com/CapitolHill/1931/ and mirrors.

It is also available as part of Debian, as of Debian 2.2, in the package named "anarchism".