W. L. Guttsman 
The German Social Democratic Party, 1875-1933 [PDF ebook] 
From Ghetto to Government

Originally published in 1981, this book covers the development of the Social Democratic Party (SPD) from its inception to the end of the Weimar republic. Within a historical framework it analyses the role and operation of the SPD in the changing social and political climate of Germany and describes the party’s internal struggles throughout the period. The party continually debated its aims and the means to achieve them. Conducted by people such as Kautsky, Bernsteina dn Rosa Luxemburg, with close links to Marx, Engels and other leaders of the international socialist movement, this debate within the party was one of the most fundamental socialist controversies, whose relevance remains today.