An accessible description of modern macroeconomics, and a defense of its policy relevance. Macroeconomists have been caricatured either as credulous savants in love with the beauty of their mathematical models or as free-market fundamentalists who admit no doubt as to the market's wisdom. In this book, Kartik Athreya draws a truer picture, offering a nontechnical description of prominent ideas and models in macroeconomics, and arguing for their value as interpretive tools as well as their policy relevance. Athreya deliberately leaves out the technical machinery, providing an essential guide to the sometimes abstract ideas that drive macroeconomists' research and practical policy advice. Athreya describes the main approach to macroeconomic model construction, the foundational Walrasian general-equilibrium framework, and its modern version, the Arrow-Debreu-McKenzie (ADM) model. In the heart of the book, Athreya shows how the Walrasian approach shapes and unifies much of modern macroeconomics. He details models central to ongoing macroeconomic analyses: the neoclassical and stochastic growth models, the standard incomplete-markets model, the overlapping-generations model, and the standard search model. Athreya's accessible primer traces the links between the views and policy advice of modern macroeconomists and their shared theoretical approach.