One of the themes of recent historiography in Enlightenment Studies focuses on how political economy gathers up so many of the key themes of the philosophers and reformers of the age into a discourse that crosses boundaries, national, institutional and linguistic. This lecture will examine this notion critically and re-assess the claim that political economy is the defining and unifying discourse of the European Enlightenment. Brief case studies will illustrate the intellectual transfer of key aspects of political economic doctrines between countries within Europe and beyond, including Latin America and India.