For nearly a century the Garden City movement has represented one end of a continuum in an ongoing debate about the future of the modern city. In 1898 Ebenezer Howard envisioned an experimental community as the alternative to huge, teeming cities. Small, planned "garden cities" girdled by greenbelts were to serve in time as the "master key" to a higher, more cooperative stage of civilization based on ecologically balanced communities. Howard soon...