The social sciences have sophisticated models of choice and equilibrium but little understanding of the emergence of novelty. Where do new alternatives, new organizational forms, and new types of people come from? Combining biochemical insights about the origin of life with innovative and historically oriented social network analyses, John Padgett and Walter Powell develop a theory about the emergence of organizational, market, and biographical novelty from the coevolution of multiple social networks. In the short run, they argue, actors make relations, but in the long run, they argue, actors make actors. Organizational novelty arises from spillover across intertwined networks, which tips reproducing biographical and production flows. This theory is developed through formal deductive modeling and through a wide range of careful and original historical case studies, ranging from early capitalism and state formation, to the transformation of communism, to the emergence of contemporary biotechnology and Silicon Vally. -- from back cover.