How a unique form of working together has built--and is critical to sustain--our age of information. Peer production describes a unique form of global collaboration that is responsible for creating some of the most vital parts of the internet. Information ecosystem powerhouses like Wikipedia and the Linux operating system were founded on principles of open cooperation, and only exist today due to the contributions of thousands, and in some cases, millions of people. In Peer Production, Benjamin Mako Hill, Christian Pentzold, and Aaron Shaw describe the central role that peer production plays in today's information environment, and how it is a much broader phenomenon than the handful of famous projects that are now household names. The book offers three core ideas: peer production functions as a critical mode of collaborative knowledge production; represents a novel type of social collaboration; and has unique advantages over previous forms of collaboration. The authors show that peer production is not just the foundation of the internet as we know it, but also the engine driving the global digital economy to generative AI. Finally, the book also charts the uncertain future of peer production as it confronts new threats and a changing digital landscape.