Both ZAPU and ZANU began campaigns of guerrilla warfare around 1966. Initially, it was rather sporadic, limited in its scope and consequences. It increased dramatically after 1972, causing destruction, economic dislocation, casualties, and a slump in white morale. In 1974, the major African nationalists groups, (ZAPU) and (ZANU), were united into the "Patriotic Front" and combined their military forces, at least nominally. These guerrilla raids led to escalation in white emigration from Rhodesia. This violent struggle became known as the Rhodesian Bush War, lasting from 1966 to 1979. The accounts of some of these guerrilla incursions into Rhodesia are described in the Peter Stiff novel, "The Rain Goddess".