Why do great cities rise and fall? Why have cities been pivotal to the dynamism and growth of America's economy? What are the threats cities face today—and what can we learn from history about how best to help our cities thrive? To discuss these questions, we are joined by Ed Glaeser, chairman of the Department of Economics at Harvard University, senior fellow at the Manhattan Institute, and one of the world’s leading experts on the economics and politics of cities. Glaeser explains that cities benefit from and encourage the human desire for proximity to one another, which can lead to new ideas, the transmission of discoveries, and entrepreneurship. But cities also are vulnerable to stagnation and decline, particularly when entrenched interests engage in "rent-seeking”— policies that keep newcomers down or out. Glaeser notes that we should avoid the temptation to develop a rigid set of policy prescriptions for every city, or to believe we know precisely how to plan cities or neighborhoods. Rather, he argues, we should favor policies that encourage innovation and development, and do not restrict the opportunity for people to cluster in the urban areas they choose.