This timely book examines the responsibility of international organizations for complicity in human rights and humanitarian law violations. It comprehensively addresses a lacuna in current scholarship through an analysis of the mandates and modus operandi of UN peace operations, offering workable normative solutions and striking a balance between the UN s duty not to contribute to international law violations and its need to discharge mandated tasks in a highly volatile environment. Building on existing scholarship on State responsibility for aid or assistance, this incisive book is the first to focus on how the complicity of international organizations in human rights and humanitarian law violations can be established. Through a re-examination of classic legal notions such as due diligence and effective control, and their application to the problem of UN responsibility for complicity, Dr. Magdalena Pacholska provides a pertinent analysis of the complex issues surrounding the UN's legal exposure for its activities in the field of peace and security. Legal advisers working for the UN and other international organizations, national Ministries of Defence, and courts with jurisdiction in this area, will find this book's insights both valuable and useful in practice. It will also be of interest to scholars and employees of NGOs with a focus on international humanitarian law and the accountability of international organizations.