1906. Translated by M. Beer and Th. Rothstein with a biographical sketch and some introductory remarks by Eugene Dietzgen: translated by Ernest Untermann. Dietzgen was an important socialist theorist whose writings exerted considerable influence on the workers' movement in the late nineteenth and early twentieth centuries. Contents: Joseph Dietzgen: A Sketch of His Life by Eugene Dietzgen; An Illustration of the Proletarian Method of Research and Conception of the World: Max Stirner and Joseph Dietzgen. By Eugene Dietzgen; Scientific Socialism; The Religion of Social-Democracy; Ethics of Social-Democracy; Social-Democratic Philosophy; The Limits of Cognition; Our Professors on the Limits of Cognition; The Inconceivable: A Special Chapter in Social-Democratic Philosophy; and Excursions of a Socialist into the Domain of Epistemology.