The Architecture of Open Source Applications volume II is now available (with all royalties being donated to Amnesty International). Edited by Amy Brown and Software Carpentry's Greg Wilson, the first volume provided case studies of 25 successful, open-source products including Audacity, Eclipse, CMake, Hadoop, and Mercurial. Each case study explains how the products are structured and, importantly, why the structure was chosen. Volume II adds another 24 case studies, including Git, PyPy, Firefox and SQLAlchemy.

Both volumes are available online and from epublisher Lulu. In the spirit of openness, both volumes are freely available under a Creative Commons Attribution 3.0 Unported licence.