This chapter examines development of the political strength of left parties as well as of unions in eighteen OECD countries. It discusses consequences of change in the distribution of power resources with reference to the political developments in Sweden. The working class, created by the Industrial Revolution, came into being in distinctly different contexts in different countries. The contexts and conditions for the organization and mobilization of the workers had been shaped over the centuries through the patterns of cleavages found between different collectivities in society and the alliances or conflicts the groups had entered into. Among the factors of significance for the mobilization of the working class in Western Europe, the timing of struggles for nationhood and the linguistic and religious cleavages were of particular importance. The contexts and conditions for the mobilization of the working class were also of significance for the shaping of the movements representing the interests of the upper and middle classes in the societies.