This chapter introduces the lifestyle and economy of pastoral nomadism, differentiating between the camel nomadism of the Bedouin and the nomads of the Eurasian steppe, who raised sheep, goats and horses. The definition of tribe is discussed, as are the controversies surrounding the concept. The chapter shows that nomadic and settled societies have been interdependent from the beginning of history. The development of mounted nomadism in the first millennium BC increased the power of nomads; a new type of camel saddled enabled trade across the Syrian desert and Arabian peninsula, with nomad dynasties controlling major trade routes. With the development of efficient horse riding, the Eurasian nomads became formidable mounted archers and formed powerful states.