In recent years, searching for source code on the web has become increasingly common among professional software developers and is emerging as an area of academic research. This volume surveys past research and presents the state of the art in the area of "code retrieval on the web." This work is concerned with the algorithms, systems, and tools to allow programmers to search for source code on the web and the empirical studies of these inventions and practices. It is a label that we apply to a set of related research from software engineering, information retrieval, human-computer...