This is the first time one of the most important of Lukacs' 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. Writing in 1968, on the occasion of the appearance of his collected works, Lukacs evaluated the influence of this book as follows:...