 Harris' earliest work began in the Boasian tradition of descriptive anthropological fieldwork, but his fieldwork experiences in Mozambique in the late 1950s caused him to shift his focus from ideological features of culture toward behavioral aspects.His 1969 history of anthropological thought, "The Rise of Anthropological Theory" critically examined hundreds of years of social thought with the intent of constructing a viable understanding of human culture that Harris came to call Cultural Materialism.The book, affectionately known as "The RAT" among graduate students, is a synthesis of classical and contemporary macrosocial theory.