Intelligence gathered through interpersonal contact with human sources
Human intelligence (HUMINT) is intelligence gathered through interpersonal contact — the recruitment and management of spies, informants, and other human sources. It is the oldest form of intelligence gathering and remains essential despite the dominance of technical collection methods like signals intelligence and satellite imagery.
The CIA's Directorate of Operations (now the National Clandestine Service) is the primary U.S. agency responsible for HUMINT collection abroad. The FBI handles domestic HUMINT operations. Military intelligence units conduct HUMINT in operational theaters. The coordination — and competition — between these entities has been a persistent source of intelligence failures.
HUMINT operations have produced both spectacular successes and catastrophic failures. Oleg Penkovsky, a Soviet military intelligence colonel recruited by the CIA and MI6 in the early 1960s, provided critical intelligence during the Cuban Missile Crisis. Conversely, the CIA's reliance on a single HUMINT source — codenamed "Curveball" — for claims about Iraqi mobile biological weapons labs contributed to the catastrophic intelligence failure that preceded the 2003 invasion of Iraq. Curveball was later revealed to be a fabricator.
