The comparison of the revolutionary movements, the seizure of power by the Communists, and the establishment and evolution of totalitarian régimes in Russia and China is a vast field of study in which little work has yet been achieved. The obvious obstacle is of course the scarcity of scholars in the non-Communist world who are familiar with the language, culture and history of both Russia and China. A truly formidable intellectual equipment is required. Dr. Karl Wittfogel and Dr. Benjamin Schwarz are outstanding among the few who possess it. One hopes that among the rising generations of the western nations the necessary combination of knowledge will become more frequent. Meanwhile those of us who have specialised in the Russian or East European field must learn what we can of China from secondary works and from those original documents which are available in translation. Well aware of the inadequacy of our understanding of Chinese affairs, we can only put to our Sinological colleagues problems which have arisen in the history of the Soviet or European Communist movements or regimes, and ask their opinions on the relevance of these problems, or on the reasons why they are not relevant, to China. It is in this spirit that the following observations are offered, as a contribution not to knowledge but to discussion. The points which I wish to raise are mainly concerned with the relationship of the Communist movement to social classes during its rise to nower.