Comparative analyses of a range of key issues related to unjustified enrichment, an important area of private law.

Part I: 1. Introduction David Johnston and Reinhard Zimmermann; Part II. Enrichment 'Without Legal Ground' or Unjust-Factor Approach?: 2. Unjust factors and legal grounds Sonja Meier; 3. In defence of unjust factors Thomas Krebs; Part III. Failure of Consideration: 4. Failure of consideration: myth and meaning in the English law of restitution Graham Virgo; 5. Failure of consideration Robin Evans-Jones and Katrin Kruse; Part IV. Duress and Fraud: 6. In defence of unjust factors: a study of rescission for duress, fraud and exploitation Mindy Chen-Wishart; 7. Fraud, duress and unjustified enrichment: a civil law perspective Jacques du Plessis; Part V. Change of Position: 8. Restitution without enrichment? Change of position and Wegfall der Bereicherung James Gordley; 9. Unwinding mutual contracts: Restitio in integrum v the defence of change of position Philip Hellwege; Part VI. Illegality: 10. The role of illegality in the English law of unjust enrichment Gerhard Dannemann; Part VII. Encroachment and Restitution for Wrongs: 12. Reflections on the role of restitutionary damages to protect contractual expectations Janet O'Sullivan; 13. Encroachments: between private and public Hanoch Dagan; Part VIII. Improvements: 14. Mistaken improvements and the restitution calculus Andrew Kull; 15. Enrichment by improvements in Scots law James Wolfe; Part IX. Discharge of Another Person's Debt: 16. Performance of another's obligation: French and English law contrasted Simon Whittaker; 17. Payment of another's debt Hector L. MacQueen; Part X. Third Party Enrichment: 18. 'At the expense of the claimant': direct and indirect enrichment in English law Peter Birks; 19. Searches for silver bullets: enrichment in three-party situations Daniel Visser; Part XI. Proprietary Issues: 20. Proprietary issues George Gretton; 21. Property, subsidiarity, and unjust enrichment Lionel Smith; Part XII. Taxonomy: 22. Taxonomy: does it matter? Ewan McKendrick; 23. Rationality, nationality and the taxonomy of unjustified enrichment Niall R. Whitty.