In Santa Cruz, California, an unusual coalition of socialist-feminists, environmentalists, social-welfare liberals, and neighborhood activists has stopped every growth project proposed by landowners and developers since 1969. Drawing on primary documents and original interviews, "The Leftmost City" utilizes Santa Cruz as a case study to critique major theories of urban power: Marxism, public-choice theory, and regime theory. The authors' findings support growth-coalition theory, which stresses the conflict between real estate interests and neighborhoods as the fundamental axis of urban politics. The authors apply insights gleaned from Santa Cruz to progressive movements nationwide, offering a template for progressive coalitions to effectively organize to achieve political power.