This study aims at exploring the crisis of the German socialist movement which grew in intensity from the time of the open split of the Social Democratic Party during the war until its climax in the bloody fighting between the radical left and moderate socialists during the so-called Spartacist Uprising of January 1919. In the course of this primary pursuit, two subsidiary aims are served: an analysis of the relationship existing between the theory and practice of the German Communists during their period of political infancy; and an examination of the impact of the Communists on the course of the German Revolution.