It is not difficult to see co-operation as the most important aspect of socialism, for co-operative societies were a recurrent feature during the whole period, and there were times when they particularly flourished – a national movement in England and Wales around 1830, extending to over 400 societies in communication with one another, a number of cooperative periodicals, and national congresses; a similar upsurge during the Second Republic in France; and a revival in both countries in the 1860s, to a large extent on the model of the Rochdale Pioneers founded in 1844, the movement continuing to grow in subsequent decades.

There are three obvious reasons why co-operation may be seen as a form of socialism. Firstly, socialists were actively involved in cooperative societies. Secondly, socialists advocated co-operation. Thirdly, co-operative societies declared their socialism. A Paris bronze-workers' co-operative society in 1850 sought ‘the growth of the welfare of the producers through the suppression of parasitic intermediaries and usurious capital, by means of the socialisation of the instruments of labour’, and ‘the emancipation of the workers by the abolition of employers (patronat)’, to achieve ‘the Republic in the workshops’, while the Stockport Working Man's Redemption Society announced ‘their object was to work for themselves instead of for masters’.

Underlying all this, of course, is the fact that co-operation, through replacing private businesses with democratic control by groups, was effecting an economic and social transformation. There were, however, several forms of co-operation. ‘The English prefer trading, the Germans credit and the French production.’