This dissertation examines the history of transatlantic Neoliberalism---individual liberty, limited government, free markets and deregulation---as it developed in the postwar period between and across the Atlantic, in Europe, Britain and the United States. The study begins in the 1940s and traces, through printed sources, government documents, private correspondence and research interviews, the flowering of a critique of the dominant New Deal liberalism and British social democracy of the mid-twentieth century, as it emerged in the ideas and arguments of Friedrich von Hayek, Ludwig von Mises and Karl Popper. The Neoliberal agenda was expanded by scholars in the United States and Britain such as Milton Friedman, George Stigler, James Buchanan, Peter Bauer and their followers and supporters in the 1950s and 1960s. A transatlantic network of 'intellectual entrepreneurs' sprang up in the same period to spread Neoliberal ideas. Neoliberalism broke through in the 1970s as events and crises---the end of Bretton Woods, the oil price shocks, Vietnam, Watergate, the breakdown of industrial relations in Britain, and most importantly, 'Stagflation'---forced policy-makers and politicians to cast around for different approaches to economic management than the Keynesian 'fine-tuning' which had dominated in both Britain and the United States. This breakthrough into mainstream politics is explored in detail through two key policy areas: economic strategy and affordable housing and urban policy. The dissertation concludes that Neoliberalism was a transatlantic movement that was generated as a political as well as an ideological movement. However, some of the policy insights provided by Neoliberal thinkers such as Milton Friedman's monetarism or George Stigler's theory of regulation should be separated from the wholesale market fundamentalism of Neoliberal philosophy. Furthermore, in terms of policy, many of the most important insights of the Neoliberals had been accepted by politicians and governments of the left---Jimmy Carter and James Callaghan---before the elections of Margaret Thatcher in 1979 and Ronald Reagan in 1980. However, the Thatcher and Reagan administrations ensured the lasting dominance of a Neoliberal political philosophy which ensured the supremacy of the market in public policy.