A series of investigations, especially in the United States and Britain, have focused attention on the performance of national intelligence services. At the same time, the onset of an era of terrorism and a broad span of trans-national security challenges has highlighted the crucial role of intelligence. This book takes stock of the underlying intellectual sub-structure of intelligence. For intelligence as for other areas of policy, serious intellectual inquiry is the basis for improving the performance of real-world institutions. The volume explores intelligence from an intellectual perspective, not an organizational one. Instead the aim of the book is to identity themes that run through these applications, such as the lack of comprehensive theories, the unclear relations between providers and users of intelligence, and the predominance of bureaucratic organizations driven by collection. A key element is the development, or rather non-development, of intelligence toward an established set of methods and standards and, above all, an ongoing scientific discourse. Here, in the transformation from an experience-based proto-science to a science of intelligence in-being, the book argues, lies perhaps the most fundamental challenge for a field of immense impact on the international community, on nations, and on individuals.