and interpretative in nature and that no substantive novelties and no substantive dissent were possible except in the guise of cautious reinterpretation of the Master’s meanings. Until his death (1895) Friedrich Engels, as the grand old man of the party, wielded an authority that was indeed challenged sometimes—by Rosa Luxemburg for instance—but never successfully or in any matter except tactics. Doctrinal leadership (with little say in practical politics) passed to Karl Kautsky (1854–1938), who had known Marx and was cut out for the role of highpriest, not least because he was not absolutely rigid and knew how to make concessions to dissent, within the inner circle of party writers, on individual points. 3 He edited the Theorien über den Mehrwert (1905–10), composed what may be called the official reply to Bernstein’s criticisms and many other pieces of apologetics and countercriticism, wrote learnedly on the economic interpretation of history, and tackled problems of applied theory, especially the question of socialist agricultural policy, thus contributing here and there even to a development of Marxist doctrine. There was nothing very original in all this. The nature of the position he had taken up from the first would have precluded originality even if he had had any spark of it. But taking Kautsky’s work as a whole, we may well speak of a historically significant performance. 4 The writers who, amidst acrimonious controversies, succeeded in working out more or less novel aspects of Marxist doctrine are usually referred to as neo-Marxists. Though the productive years of most of them fall within the period under survey, many of their publications belong to the next. We adopt, however, the same practice that we also follow in some other matters, namely, the carrying of our survey down to the present in