Social democratic parties and the system of social democracy are a central part of political life in the West. This book focuses on social democracy as a party and a broad movement as well as a unique political force in the industrialised world. It provides a critical comparative survey of when, where, how and why social democracy developed within established capitalist democracies. It explains the electoral successes and failures of social democratic parties, the influence of the party system and the nature of competition and co-operation between parties. It also examines the ideological tensions within social democratic parties between socialists and reformists. It features a broad range of case studies including Australia, Austria Belgium, Denmark, Finland, France, Greece, Germany, Italy, Luxembourg, Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom as well as comparisons with the United States, Canada and Japan.