AEJ: Microeconomics is the American Economic Association's field home for microeconomic theory one tier below AER's general-interest bar. It publishes micro theory, game theory, mechanism and market design, and theoretical IO — theoretical contributions with general results, established formally. The contribution can be field-specific rather than discipline-wide, but the theory must be correct, general, and economically interesting; this is the home for serious theory that is excellent but narrower than a top-5 or Econometrica swing.