Scholars have long argued that transparency makes international rule violations more visible and improves outcomes. Secrets in Global Governance revises this claim to show how equipping international organizations (IOs) with secrecy can be a critical tool for eliciting sensitive information and increasing cooperation. States are often deterred from disclosing information about violations of international rules by concerns of revealing commercially sensitive economic information or the sources and methods used to collect intelligence. IOs equipped with effective confidentiality systems can analyze and act on sensitive information while preventing its wide release. Carnegie and Carson use statistical analyses of new data, elite interviews, and archival research to test this argument in domains across international relations, including nuclear proliferation, international trade, justice for war crimes, and foreign direct investment. Secrets in Global Governance brings a groundbreaking new perspective to the literature of international relations.