Although boundaries, including freshwater ones, are generally set by treaties concluded by the states concerned, interpretation of such agreements by the different states has varied, resulting in a number of disputes before international tribunals. The aim of this monograph is to describe and analyze the different methods applied in the delimitation of international rivers and lakes and the recent developments in this field. The monograph reassesses these diverse methods of boundary delimitation in view of the latest and abundant jurisprudence of the International Court of Justice and the tribunals under the aegis of the Permanent Court of Arbitration on the subject. The monograph also focuses on the influence of human considerations in the field under study and the legal consequences ensuing therefrom, in addition to drawing some conclusions regarding freshwater boundaries.