The life of a counterintelligence (CI) operative has been immortalized in film and novels as being filled with glamour and excitement. While international travel, heroism, and danger are all part of the job description, the fundamentals of counterintelligence are discipline, skill, and—well—intelligence. CI operations include conducting investigations, offensive and defensive operations, security and vulnerability analyses, and intelligence collection in peace and at all levels of conflict to support command needs. This guide serves to inform commanders, agents, and analysts on how to identify, neutralize, and exploit any foreign attempts to conduct operations against the U.S. Army. Find out how CI operatives combat terrorism, create battlefield deception, and inform all echelons of combat of both real and potential threats from the U.S. Army's own guide to counterintelligence. The tactics, techniques, and procedures (TTP) outlined are the same instructions that CI personnel follow in the field. As the world becomes more interconnected and as technological advances continue to be made, proper CI techniques are exceedingly critical to the protection of the U.S. Army. Counterintelligence is not just the subject for an entertaining story, it is how peacekeeping, humanitarian, and counter-drug operations are carried out in this globalized world.