I. The Market Power Paroxysm and the Antitrust Paradigm. 1. Market Power in an Era of Antitrust. 2. ‘The Faltering Political Consensus Supporting Antitrust. 3. Preventing the Political Misuse of Antitrust. 4. Recalibrating Error Costs and Presumptions. 5. Erroneous Arguments against Enforcement. II. Antitrust Rules and the Information Economy. 6. Inferring Agreement and Algorithmic Coordination. 7. Exclusionary Conduct by Dominant Platforms. 8. Threats to Innovation from Lessened Competition. 9. Harms to Suppliers, Workers, and Platform Users. III. Looking Forward. 10. Restoring a Competitive Economy