The book focuses on the current state of the law of international watercourses. Progress and management paradigm shifts of the regime of uses and environmental protection of the international watercourses (1815–2008) are examined through the main sources of international law. Current state of the law is demonstrated by analysing the transition of the various concepts and approaches (i.e. international river to international basin), substantive principles (i.e. absolute sovereignty to equitable utilisation), implementation mechanisms (i.e. piecemeal to integrated management) and dispute settlement venues (i.e. adjudication to impartial fact-finding). The present state of the law recognises developmental needs and environmental considerations as equal, establishing parity between the regimes of uses and environmental protection. The findings can be helpful to determine how the law of international watercourses, particularly relevant treaties, has to be aligned with sustainable developments, elaborating the prospects for an integrated legal perspective, combating the adverse impacts of the global hydro-climate change.