From the long viewpoint of history of economics, the two most important contributions that Jan Tinbergen made to economics are surely the development of the first macro-econometric model and a general theory of economic policy-making. This paper explores these two innovations to recover why they deserve such recognition, analyses their technical and conceptual depths, and shows how they relate to the economic history of the period and his personal history. In the process, it becomes clear that they are not separate innovations, but, as Tinbergen recognised, involved the same logic; and as we can recognise, were driven by the same ambition to make economics usable in the world.