In this groundbreaking study of the Workers' Party-the first legal mass party on the left in Brazil's recent history-Margaret E. Keck sheds new light on significant changes in Brazilian political organization and society over the past two decades. Her book not only clarifies political movements in Brazil and Latin America but also gives insights into attempts in any country to create democratic parties that represent the popular classes. "A wonderful book. The arguments are convincing, the prose, refreshingly clear...Her study will likely be foundational and indelible for subsequent scholarship on the Workers' party."-Ben Ross Schneider, American Political Science Review "An important contribution to studies of contemporary party politics, its comparative value is enhanced by systematic reference to work on party formation and organization in Europe."-Paul Cammack, Political Studies