This thesis, written fifteen years ago, has its own reputation; and it is because it has been so often refrred to that it is now published, unchanged but with a supplementary bobliography. The discussion of the finds from the two sites of Mleiha and ed-Dur is important both locally and regionally, and to wider historical questions such as the population and culture of pre-Islamic Arabia, the spread of Mediterranean culture and the general development of Arabia in the centuries before Islam.