International intelligence cooperation is a long-established dimension of intelligence work but in recent years it has become a defining feature of intelligence services’ activities. The scope, scale and significance of cooperation have increased exponentially over the past two decades, and particularly since 2001. Globalisation has facilitated the proliferation of transnational threats which have induced intelligence services to cooperate with a broader range of international contemporaries on an evergreater range of issues. This volume has demonstrated that intelligence sharing remains the principal manifestation of international intelligence cooperation. Yet, within the past decade we have witnessed a dramatic increase in joint operations to collect intelligence, as well as the development of joint analysis centres. While international intelligence cooperation remains dominated by bilateral relationships, multilateral cooperation has become increasingly common; this is not only the case in the EuroAtlantic region, but also in Africa through forums such as the Committee of Intelligence and Security Services of Africa, and in Asia within the context of the Shanghai Cooperation Organisation. These trends have been primarily evident in the fight against international terrorism, where intelligence cooperation between states has been elevated to the level of UN Security Council obligation.2 It is also in the context of counter-terrorism that intelligence cooperation has presented ever greater challenges to accountability, human rights and the rule of law. Revelations about the counter-terrorism activities of intelligence services have continued to emerge at a torrential rate. Many of the revelations which have left us in a state of ‘frozen scandal’ have involved intelligence cooperation.3 This volume has shown that various manifestations of intelligence cooperation give rise to concerns about accountability, human rights and the rule of law. However, the pre-eminent cause for concern is intelligence cooperation with so-called ‘non-traditional partners’ that do not uphold the same human rights standards, and are not subject to democratic oversight.