Introduction: Understanding implied obligations: reasoning and methodology; Part I. Grounds for a Supplemental Approach: 1. Individuals and relationships; 2. Authority's limits; 3. Promises and obligations; 4. Maximization and cooperation; Part II. Values-balancing Legal Reasoning: 5. The foundations of value-balancing legal reasoning; 6. The scope of obligations; 7. The source of obligations; 8. Relationality redux: law on the ground and law on the books; Part III. Applications: 9. Legal enforceability: formation; 10. Performance obligations: methodological issues; 11. Performance obligations: the values-balancing approach; 12. Consumer contracts and standard terms; 13. Excused performance and risk allocation; 14. Remedies; Conclusion.