The thesis provides the first overall history of the World Bank Group's International Centre for Settlement of Investment Disputes (ICSID) and of its constituent treaty, the 1965 Convention on the Settlement of Investment Disputes between States and Nationals of Other States. The thesis traces the immediate origins of the Convention, in the years 1955 to 1962, and gives a stage-by-stage narrative of the drawing up of the text of the Convention between 1962 and 1965. Next recounted are details of bringing the Convention into force in 1966 and the elaboration of the initial versions of the Regulations and Rules of ICSID adopted at the first meetings of its Administrative Council in 1967. The three periods 1968 to 1988, 1989 to 2000 and the 2000s up until June 30, 2010, are covered in subsequent chapters of the thesis. Examined in these chapters are expansions of the Centre's activities and changes made to the Regulations and Rules over the years. Also furnished in these chapters are overviews of the conciliation and arbitration cases submitted to ICSID in the respective periods. The overviews are followed by in-depth discussions of selected cases and key issues in them. The concluding chapter discusses some of the broad themes and findings of the thesis and several suggestions for further changes at ICSID to help ensure its continued success.