This book has dual origins. One is in the thirty-five years I spent as a professional intelligence practitioner, after two earlier ones as a national serviceman in the British Intelligence Corps just after the Second World War. This career coincided almost exactly with the Cold War. It was spent mainly as a member of a collection agency, with spells in other intelligence jobs in the Cabinet Office and the Ministry of Defence. Over the years I became increasingly interested in how big intelligence institutions operated, and in the way they fitted together into a national ‘system’. By accident or inclination my viewpoint came to be that of an Organization Man.

The second origin is in the contact I was free to make after retirement with the world of scholarly ‘intelligence studies’ (mainly in the United States and Canada but now developing in Britain), and with the academic faculties in which it is based. I was able to do some writing and teaching about intelligence and explore its literature. My base in Nuffield College Oxford also helped me to make some forays into social science's studies of organizations and their transmission and use of information.

From these origins has come this attempt to add to existing theory about intelligence power and the institutions through which it works. By ‘theory’ I mean nothing more than concepts and generalizations that seek to explain things.