Publisher Summary This chapter examines Macromoli, a worldwide catalog of economic models. The main ideas are outlined for a direct access catalog of macroeconomic models as used for theory and application. The unity of the various model-building strategies is shown in the chapter. The most important and empirically well-established typical model maps, such as diagrams, summary exhibit, systems of equations, analogue representations, are outlined in their use by example for the catalog. The chapter attempts to include the full breadth of numerical economic model, such as mainline Keynesian–Tinbergen–Klein–Leontief systems, monetarist models, computable general equilibrium models, and simulation models. Even if an emphatically stressed claim of a most distinct theoretical background is raised, the empirical end products—the finally implemented systems—often except for nuances in the coverage of variables do not look so much different from each other. It is suggested that smallness plays a role in representation, when large models are presented by miniature models.