Volume 24 contains works Marx and Engels wrote from May 1874 to May 1883. These years saw the beginning of a new stage in the development of the working-class movement, a period when the first mass proletarian parties were formed in different countries. Marx and Engels now concentrated their efforts on uniting the workers’ movement ideologically on the basis of scientific socialism and on further development of revolutionary theory. They devoted considerable attention in these years to the economic and social situation in Russia and to the development of the workers’ movement there. Using the example of Russia, Marx and Engels worked out their ideas on the possibility of countries pursuing the non-capitalist path of development.