How can we explain the variation of Corporate Responsibility (also known as CSR and Corporate Citizenship) - business's voluntary engagement for social and environmental ends above legally mandated minimum standards? This thesis develops a political-economic explanation for CR's temporal and cross-national variation. It argues that Corporate Responsibility has elective affinities with economic liberalization and market liberalism, and functions as a material and symbolic substitute for institutionalized forms of social solidarity. The erosion and dismantling of Institutionalized Social Solidarity (ISS) is associated with the rise of CR. The dynamics of the response may be country or Variety of Capitalism specific. Both employers and state officials have an interest in compensating for the hardships of liberalization and the weakening of institutionalized social solidarity. One way in which they seek to legitimate the market vis-à-vis their 'stakeholders' and the electorate, and justify themselves vis-à-vis their own conscience, is through Corporate Responsibility. Those in the engine rooms of contemporary capitalism want to perceive themselves as serving the common good. This is true irrespective of capitalist 'varieties.' Using Corporate Responsibility Associations (CRAs) as a proxy for the institutionalization of CR, the thesis tracks the growth and spread of CR across Europe and beyond. Chapters illustrate the co-evolution of CR and Thatcherism in the UK since the late 1970s; the rise of CR and the decline of Organized Capitalism in Germany since the mid-1990s; the conversion and contestation of EU-level CR since the 1990s; and CR's spread and variation across the OECD. The thesis concludes by reflecting on the outlier case of New Zealand, on the transnational networks of CR, and on the ambivalence of responsible business in contemporary capitalism. CR is not only part of the solution to pressing problems, but - as a complement to marketliberalism and a substitute for institutionalized social solidarity - part of the problem