This is the first time one of the most important of Luk cs' early theoretical writings, published in Germany in 1923, has been made available in English. The book consists of a series of essays treating, among other topics, the definition of orthodox Marxism, the question of legality and illegality, Rosa Luxemburg as a Marxist, the changing function of Historic Marxism, class consciousness, and the substantiation and consciousness of the Proletariat...