Joel Kotkin is the author of "The City: A Global History". His other books include "The New Geography: How the Digital Revolution Is Reshaping the American Landscape," "Tribes: How Race, Religion and Identity Determine Success in the New Global Economy" and "California, Inc.". He is now working on a book about the American future. He a presidential fellow in urban futures at Chapman University in Orange, Calif., and a senior fellow at the New America Foundation. He has written for The New York Times, Inc. magazine, The Wall Street Journal, The Los Angeles Times and Politico.