For centuries human society in the Middle East has been divided into three different types of communities - nomads (Badawin), settled culti vators (Hadhar) and townspeople. Through history, many writers have been impressed by the contrasts in ways of life and social organization shown by these three groups; and until recently there was a tendency to stress the isolation of the cultivators and the Badawin from the ‘ civilizing’ influences of urban life. P. W. English, however, has put forward a modified approach - the concept of the Middle East ecological trilogy. He emphasizes that although Middle East society was divisible into three distinct types of communities, these were mutually dependent ‘ each with a distinctive lifemode, each operating in a different setting, each contributing to the support of the other two sectors and thus to the maintenance of total society’ . Commerce was one activity which played an important role in the development of close mutual relations within this ecological system. Besides the merchant body directly engaged in exchange of products, the organization of long-distance transport involved a supply of foodstuffs and other agricultural products, and hence the Hadhar of the rural areas were involved. Badawin were also employed as guides and drivers; and safe conduct money was sometimes paid to nomads. Woodmen, tent and harness makers also had a marginal part to play. Nevertheless, the benefits of this interdependence were unequally divided, and urban dominance is central to the concept of the ecological trilogy. Recent changes, however, have disturbed the equilibrium between these three communities, and the forces of modernization are producing new patterns and new relationships.