The law of international investment treaties has emerged as a distinct and important field of international law. International investment treaties concern the regulation of the behavior of sovereign States towards foreign investors. Over the past 30 years, the relationship between foreign investors and States has become dominated by bilateral and multilateral investment treaties of which there are presently some 2,600 in force. Virtually all states are a party to at least one, sometimes dozens, of these treaties. Under an investment treaty, the State agrees to accord foreign investors - and only foreign investors - certain standards of treatment and levels of protection with respect to the foreign investor's investments in the country. In addition, the State agrees to subject itself to binding international arbitration to resolve claims brought by foreign investors alleging that the host State has failed to provide the treatment agreed upon in the treaty. The stakes in such disputes are often very high, with claims and awards sometimes reaching billions of dollars. The legal fees are high as well, averaging approximately USD 5 million per party. Granting special substantive and procedural rights to foreign investors raises difficult and important legal and policy questions: What are the costs and benefits of granting foreign investors international rights which go beyond those afforded to domestic investors? To what extent does the threat of arbitration under these treaties limit the State's legitimate exercise of its power to regulate for the public good and meet other international obligations? Is international arbitration, with its reliance on private lawyers as advocates and arbitrators, the best method for resolving these kinds of disputes? This series of lectures examines these questions, addressing both the legal doctrine and the practice of investment treaties and the disputes arising under them. Students will be asked to read selections from a variety of texts and articles and international investment treaties and arbitral awards. At the end of the course, students will (1) understand the contextual and theoretical underpinnings of the subject; (2) have familiarity with the core principles of international investment treaties and the resolution of investment treaty disputes between investors and States; and (3) be able to critically evaluate the rules, policies, and principles of the investment treaty regime.