This book deals with the question of national sovereignty and States' participation in International Organizations, whether traditional or supranational ones. Although there has been much discussion on the problems posed by the transference of sovereignty, this volume provides an original insight in that transfer of state sovereignty is approached as a dynamic process that can be divided into three different phases. Part one, called `the initial phase', focuses on the examination of the domestic legal basis for the transfer of state sovereignty. Part two, `the transfer phase', investigates how the process of transfer evolves within the core of two International Organizations: the United Nations and the European Communities. Part three, `the post-transfer phase', analyses the States' responses to the effects and consequences of the transfer of sovereignty.