A great selection of highly influential, older and contemporary anarchist writings can be found at the links below. The F.A.Q. link is a great starting point for learning the basic concepts. The last link pertains to Situationist theory, which is a very close relative to anarchist theory and practice, born out of the French revolutionary student movement of the 1960's. 

 

Answers to frequently asked questions about anarchism

 

A huge library of highly influential modern anarchist writings by the notorious and controversial CrimethInc. Collective

Many Classic Anarchist Writings

A glossary of Situationist terms and concepts