Hahn on Methodology: The Quest for Understanding addresses two fundamental questions: (i) what is distinctive about economic theorising?; (ii) what is the cognitive value of the outcome of this activity of economic theorising, i.e. economic theory. We will argue that for Hahn, economic theorising is distinctive with respect to four dimensions. Firstly, the aim of economic theory is neither to describe nor explain the real economic world, as in the physical sciences. Rather the aim is to achieve objective, but non-scientific, understanding. Secondly, the central question for economic theory remains for Hahn how to understand, but not to predict as in physics for instance, how decentralised choices interact and perhaps get co-ordinated. Thirdly, Hahn identifies ‘three commitments’ without which, he argues, economic theorising for him is not possible. Finally, economic theorising has a distinctive approach, which Hahn calls its ‘grammar of argumentation’ .