Lorenzo Gasbarri is Research Fellow in International Law at Bocconi University. He has studied at the University of Florence, the University of Milan and at the Graduate Institute in Geneva. Dr Gasbarri has held research positions at University College London, and at the University of Helsinki. He has been a Visiting Fellow at the University of Copenhagen and at the Max Planck Institute for Comparative Public Law and International Law. He is Junior Editor of the Oxford Database on International Organizations and he convenes the interest group on the law of international organizations of the European Society of International Law.

• 1: Introduction 2: Functionalism 3: Constitutionalism 4: Informalism 5: Exceptionalism 6: Interim Conclusions 7: A Venture into Legal Theory 8: The Dual Legal Nature in Practice 9: The Law of Treaties 10: Validity and ultra vires Acts 11: International Responsibility 12: Conclusion Bibliography Index

Lorenzo Gasbarri is Research Fellow in International Law at Bocconi University. He has studied at the University of Florence, the University of Milan and at the Graduate Institute in Geneva. Dr Gasbarri has held research positions at University College London, and at the University of Helsinki. He has been a Visiting Fellow at the University of Copenhagen and at the Max Planck Institute for Comparative Public Law and International Law. He is Junior Editor of the Oxford Database on International Organizations and he convenes the interest group on the law of international organizations of the European Society of International Law.

• 1: Introduction 2: Functionalism 3: Constitutionalism 4: Informalism 5: Exceptionalism 6: Interim Conclusions 7: A Venture into Legal Theory 8: The Dual Legal Nature in Practice 9: The Law of Treaties 10: Validity and ultra vires Acts 11: International Responsibility 12: Conclusion Bibliography Index

Lorenzo Gasbarri is Research Fellow in International Law at Bocconi University. He has studied at the University of Florence, the University of Milan and at the Graduate Institute in Geneva. Dr Gasbarri has held research positions at University College London, and at the University of Helsinki. He has been a Visiting Fellow at the University of Copenhagen and at the Max Planck Institute for Comparative Public Law and International Law. He is Junior Editor of the Oxford Database on International Organizations and he convenes the interest group on the law of international organizations of the European Society of International Law.

• 1: Introduction 2: Functionalism 3: Constitutionalism 4: Informalism 5: Exceptionalism 6: Interim Conclusions 7: A Venture into Legal Theory 8: The Dual Legal Nature in Practice 9: The Law of Treaties 10: Validity and ultra vires Acts 11: International Responsibility 12: Conclusion Bibliography Index