John Maynard Keynes was, probably, the political economist most acutely aware of the inadequacies of unfettered capitalism and of Soviet-style socialism. His social philosophy, to be most appropriately called social liberalism, does not form a tight system but is scattered over the whole of his work. The economic theory associated with the doctrine of social liberalism is classical-Keynesian political economy, the synthesis of post-Keynesian economics at the level of principles and, as such, the alternative to (liberal) neoclassical-Walrasian economics. This chapter explores the classical-Keynesian political economy, its genesis, its present state, and its implications for political philosophy and economic policy. It examines the making of classical-Keynesian political economy, the classical-Keynesian system of political economy, the role of finance and the interactions between the real and the financial sector, and classical-Keynesian political economy in the wider context of political philosophy and socioeconomic policies. The chapter concludes by considering some issues of transition from capitalism to social liberalism.