Book excerpt: Throughout the War in Southeast Asia, Communist forces form North Vietnam infiltrated the isolated, neutral state of Laos. Men and supplies crossed the mountain passes and travelled along an intricate web of roads and jungle paths known as the Ho Chi Minh Trail to the Viet Cong insurgents in South Vietnam. American involvement in Laos began which a photo-reconnaissance missions and, as the war in Vietnam intensified, expanded to a series of air-ground operations from bases in Vietnam and Thailand against fixed targets and infiltration routes in southern Laos. This volume examines this complex operational environment. United States Air Force. Center for Air Force History.