Abstract: This paper is a preliminary draft of a chapter for eventual inclusion in the Handbook of International Economic Law, edited by Andrew T. Guzman and Alan O. Sykes, forthcoming 2006 from Edward Elgar Publishing. The chapter is a survey of the field of international finance from the perspective of law and regulation. Its principal focus is the decision as to what rules to apply in the regulation of banking, securities and sovereign debt - home or host country, or international.