In 1964 a right-wing military coup seized power in Brazil. The Araguaia Guerrilla movement, formed by the Communist Party of Brazil in the late 1960s, launched an armed opposition to the US-backed military government with the intention of waging a Maoist-style people's war from its base area along the banks of the Araguaia river. Between 1972 and 1974 the Brazilian military launched a brutal campaign to destroy the Araguaia Guerrilla in its jungle stronghold.

While the idea of armed opposition to the military government of Brazil was popular amongst the Brazilian left-wing, it was the Communist Party of Brazil (PCdoB) that actually formed such a movement. They selected as their base area the towns along the banks of the Araguaia River where tensions between locals and the government-backed mining operations already existed. The concept was that a rural people's war would be waged from this base area, inspired by Mao's campaign in the Chinese Civil War and the successful Cuban Revolution. Never a large organization, the Araguaia Guerrilla movement avoided much attention of the government until 1972 when the military launched a campaign that by 1974 would leave few survivors.

Araguaia War examines the military regime in Brazil between 1964 and 1985, and the subversive groups, both urban and rural that appeared in that country in the late 1960s and early 1970s. The Brazilian military and police forces in the 60s and 70s are described in detail, along with their campaign against the armed opposition in Araguaia, in the states of Maranhão, Pará and Goiás, and the actions of the guerilla movement.