This Introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book addresses the pre-history of Social Democracy from the aftermath of the French revolution of 1789 to the setting up of the first workers' parties in the 1860s. It explores the development of the Social Democratic Party of Germany (SPD) in West Germany since 1945. The party consciously attempted to overcome its old confinement to a specific working-class milieu and decided against the resurrection of its manifold ancillary organisations. The book provides the reader with an introduction to some of the most important literature on the history of the German labour movement. It discusses the 'greening' of the SPD in the 1980s, has been a direct consequence of such re-thinking which undoubtedly received a vital boost from the SPD's fear of losing votes to the Greens. The book discusses some of the major long-term characteristics of German Social Democracy.