The purpose of this thesis is to examine several important aspects of social democracy in the Cisleithanian half of the Habsburg Monarchy in the years between 1867 and 1901. By exploring the environment in which the socialist movement developed, the socialist ideology, the development of the party and its organization, and the socialist leadership, it presents a profile of the Cisleithanian socialist movement. In spite of the fact that the socialist movement in Cisleithania was one of the largest in Europe by 1901, historians have tended to ignore both its development and its peculiarities. The Cisleithanian socialist movement, and particularly its German-speaking component, has been seen as merely a junior partner of the Reich-German socialist movement. To a certain extent this was true, for Cisleithanian socialists did import their ideology and their original conceptions of party and trade union organization from Germany. Yet the models imported from Germany all had to be adapted to the multi-national character of the socialist movement in Cisleithania. Marxism was adopted, but Cisleithanian socialists were forced to take a position on the complex nationality question in Cisleithania, a question for which there was no acceptable Marxist "answer." The German idea of a centralized party organization was also taken over, but it had to be abandoned in face of demands for autonomy on the part of Czech socialists. An entirely new and unique form of party organization was evolved. In the trade union movement, the concept of centralism was also adopted, and once more proved unsuitable in a multinational environment, in spite of convincing arguments in its favour. In these respects, and others, Cisleithanian socialists made an important contribution to the development of the European socialist movement, a contribution which deserves more attention from historians than it has received. The major problem the Cisleithanian social movement faced was the nationality question. The multi-national nature of the state and the socialist movement, in a context in which nationalist feeling was very strong, helped to determine both the development and the fate of the socialist movement of all nationalities in the western half of the Monarchy. In fact, the nationality conflict which developed in the Cisleithanian socialist movement mirrored the conflict in Cisleithania as a whole. Indeed, the contradiction between the theory of socialist internationalism and the practical reality of nationalism in the working class was apparent in the Cisleithanian socialist movement long before the outbreak of the First World War made it clear to non-socialists and socialists alike. In this sense, the study of the Cisleithanian socialist movement is also a study in nationalism. / Arts, Faculty of / History, Department of / Graduate