Architecture of Open Source Applications is a very well-reviewed series of books that gives a high-level view of the architecture of various open-source software projects. This first volume focuses on well-known projects, such as BerkeleyDB, Eclipse, LLVM, Mercurial, Selenium, and Sendmail.- Architecture of Open Source Applications　is a very well-reviewed series of books that gives a high-level view of the architecture of various open-source software projects. This first volume focuses on well-known projects, such as BerkeleyDB, Eclipse, LLVM, Mercurial, Selenium, and Sendmail.