Discusses the effects of the world's increasing urban population on the environment and on our quality of life. Addresses issues such as transportation, urban sprawl, socioeconomic divisions, and pollution. Looks at what sustainability means in locations as diverse as East L.A., Vancouver, Portland, and Sô Paulo and Curitiba, Brazil. Includes commentary by Jane Jacobs, Bill McKibben, Bill Rees, California senator Martha Escutia, and John Ryan.