This historical and comparative ethnography of the Oromo of the Horn of Africa is based on the teachings of the custodians of the sacred knowledge traditions. It shows that central to their traditional systems of thought and belief was the concept of 'time-force', which may once have formed part of a wider, shared, regional culture. The study presents a number of new findings about the cultural history of the Oromo. With maps, diagrams, photographs, glossary and index.