The co-operative movement was founded upon principles of democratic member control and was Britain’s biggest consumer organisation. By the mid-twentieth century, the British retail societies alone boasted a membership of over 12.5 million. Anyone could join a co-operative retail society provided they were over 16 years of age. There was a small payment of an entrance fee in the form of a £1 ‘share’, which could be paid up at once, or at a set rate per quarter, or could be raised by allowing dividend to accumulate in a share account. Unlike in other businesses, each member was entitled to one vote whatever the amount of their shareholding. The primary unit of the co-operative movement was the local retail co-operative society. These societies varied in size from small village ones with a few hundred members to larger, city-based societies with over a hundred thousand members. This chapter explores how co-operative ideology was disseminated at a grass roots level, and how this ideology was adapted and changed over time. It explores central concepts associated with the co-operative movement, including opposition to capitalism, the role of the dividend and democratic control.