Can the economic history of Detroit be told without Henry Ford and Alfred Sloan? Would Ford have achieved the same success if he had worked in Houston? Would Silicon Valley have experienced its remarkable growth without Frederick Terman and William Shockley? Entrepreneurs often seem to have been significantly influenced by features of their local economies, and they have often influenced the fates of those economies. Yet, urban economists have only infrequently looked directly at the local causes and consequences of entrepreneurship, including policies and programs carried out by local and state governments in those regions. Join Edward L Glaeser professor of economics at Harvard University and director of Harvard's Rappaport Institute for Greater Boston as he ponders the question of why clusters of entrepreneurs exist in some areas and not in others?