This chapter introduces the key terminology about outsourcing intelligence and provides theoretical framework for the book. The line between the public and private sectors has been blurred and debate on this topic has moved to intelligence tasks much further than it has ever before. The leading firms and individuals at the centre of this issue are a new phenomenon known as Private Intelligence Contractors or PICs. PICs are private entities and persons who perform a broad scope of intelligence tasks for intelligence agencies. Remarkably they provided sensitive services such as intelligence collection, interrogation, intelligence analysis and target identification which were customarily carried out by government employees. PICs have therefore challenged the traditional approach which assumes that sensitive intelligence tasks should be performed by government officials because of their importance for national security. This chapter also provides the rationale for testing the principal-agent theory to examine the research questions through three cases studies after 9/11: (1) the Iraqi WMD issue, (2) the Abu Ghraib prison scandal, and (3) US covert drone operations. The principal-agent theory is a useful approach for demonstrating whether an agent pursues the best interest of the principal. To measure the agency problem in each case, this chapter first determines the role(s) of the actors, then demonstrates how to measure agency problems by the implementation of police-patrol and fire-alarm oversight mechanisms. The main focus here is not only that private contractors were delegated to intelligence tasks but also that the executive principal tried to increase his discretion and achieve his hidden agenda by mismanagement, politicisation and the outsourcing of intelligence. This chapter also discusses the response of the executive and legislative principals for each case and Congressional attempts to fix the existing police-patrol mechanism.