The works collected here are but a small part of what Engels wrote in connection with Marx’s Capital. For over half a century, Engels creative activity was closely interwoven with that of marx. The correspondence of the founders of Marxism shows the extremely active share Engels had in the elaboration of a number of the most important propositions of Capital and what a constant help he was to Marx by his advice, his factual information and his critical remarks. Many of Engel’s works are devoted to the development and substantiation of the basic propositions of the Marxian doctrine.