Society is no longer based on mass consumption but on mass participation. New forms of collaboration - such as Wikipedia and YouTube - are paving the way for an age in which people want to be players, rather than mere spectators, in the production process. In the 1980s, Charles Leadbeater's prescient book, In Search of Work, anticipated the growth of flexible employment. Now We-think explains how the rise of mass collaboration will affect us and the world in which we live.