The Introduction outlines the book’s conceptual foundations, starting with a theory of political economy as constitution that builds on both economic and political thought to conceptualise the relationships between the economic and the political bodies. Accordingly, the body politic is an orderly arrangement of individuals and groups fitting a collective condition, or purpose, which would at a minimum include the persistence of the political body itself. Similarly, the economic body is an orderly arrangement of individuals and groups fitting a systemic condition for material sustenance and welfare, which would at a minimum ensure resilience of an organised economic sphere. The theory of political economy shows shifts between a focus on dispositional activities (such as allocation of capabilities or resources) and a focus on material and social interdependencies. This dynamic often makes it difficult to identify the underlying unity of political economy. Reductionist theoretical developments, both in economic and in political theory, have failed to address the embeddedness and mutual shaping of dispositions and structures at multiple levels of aggregation in the economy and the polity. The Introduction sketches a new theoretical framework that avoids both types of reductionism by highlighting the close integration between human dispositions and socio-economic interdependencies.