Drawing on his long experience in intelligence the author examines the ethical problems that intelligence activity can create. He explores each of the topics under consideration - official secrecy, security, deception, command - in the light of his extensive direct experience in decades when technical developments like radio interception and satellites have revolutionized intelligence-gathering. He proposes a doctrine for the guidance of intelligence officers of minimum trespass which parallels the military doctrine of minimum force. Professor Jones also wrote Most Secret War, Future Conflict and New Technology and Instruments and Experiences.