Cargo cults are movements that have repeatedly arisen in Melanesia over the past century as a means of achieving a millennium on earth through attaining the manufactured articles possessed by Europeans. In accord with the fundamental belief system of the Indigenes, these objects will be gained by learning the proper ritual that will induce or make the ancestor spirits send them the “Cargo.” The missionaries were thought to be teaching the ritual by means of which Europeans obtained manufactured goods from their ancestor spirits. This article starts with a study of a man who ritually sacrificed humans as part of his Cargo ritual and describes several Cargo movements. It follows the development of the cultist beliefs and acts from mass hysteria to mass paranoia as disillusionment and frustration increased and self-esteem declined; and it offers an understanding of the Indigenes' orientation to life and ways of thinking through the use of psychoanalytical theories and Piaget's concepts of cognitive development. Cultist thinking, with its profound ethnocentricity, poor boundary formation, and cognitive regression, contributes to our understanding of schizophrenic thinking. Finally, the political advantages and disadvantages of millenarism for the Indigenes of Papua/New Guinea in particular, and for disadvantaged and alienated groups in general, are considered.