Book excerpt: Mass collaboration on Internet platforms like Wikipedia and Scratch, along with wider movements like the maker space and citizen science, are poised to have profound impacts on learning and education. Bringing together researchers from such fields as: psychology, education, information technology, and economics, the book offers a comprehensive overview of mass collaboration, novel, cross disciplinary, theoretical accounts, and methodological approaches for studying and improving these massively collaborative enterprises. The book is aimed to serve as an information source for researchers, educators, and designers of platforms and learning environments.