Every once in a while, AnnaLee Saxenian, the dean of the School of Information and a professor in the Department of City and Regional Planning at UC Berkeley, will find herself in a meeting where someone decides to explain to her why Silicon Valley has been so spectacularly successful. Her interlocutor will tell her a story of ever-evolving networks, of workers who leap from startup to startup, of companies that fail and then recombine with other failures into big successes. Says Saxenian, laughing a little, “I’ll just sit there and say, ‘Oh really? Yeah, I think I have heard about that.’”