Part I. Introduction: 1. Delegation under anarchy: states, international organizations, and principal-agent theory Darren G. Hawkins, David A. Lake, Daniel L. Nielson and Michael J. Tierney; Part II. Variation in Principal Preferences, Structure, Decision Rules, and Private Benefits: 2. A problem of principals: common agency and social lending at the multilateral development banks Mona Lyne, Daniel L. Nielson and Michael J. Tierney; 3. US domestic politics and international monetary fund policy J. Lawrence Broz and Michael Brewster Hawes; 4. Why multilateralism? Foreign aid and domestic principal-agent problems Helen V. Milner; 5. Distribution, information, and delegation to international organizations: the case of IMF conditionality Lisa L. Martin; 6. Delegation and discretion in the European Union Mark A. Pollack; Part III. Variation in Agent Preferences, Legitimacy, Tasks, and Permeability: 7. How agents matter Darren G. Hawkins and Wade Jacoby; 8. Screening power: international organizations as informative agents Alexander Thompson; 9. Dutiful agents, rogue actors, or both? Staffing, voting rules, and slack in the WHO and WTO Andrew P. Cortell and Susan Peterson; 10. Delegating IMF conditionality: understanding variations in control and conformity Erica R. Gould; 11. Delegation to international courts and the limits of recontracting political power Karen J. Alter; Part IV. Directions for Future Research: 12. The logic of delegation to international organizations David A. Lake and Mathew McCubbins.