This study is intended to be a contribution to three distinct areas of investigation – the modern history of the Arabian Peninsula, the foreign policies of Third World states, and the international consequences of revolutions. Each is an area on which a substantial amount has been written in recent years, and it is hoped that the analysis in detail of twenty years of South Yemen's foreign policy will contribute to this literature, to a better understanding of this part of the Middle East, and to more documented study of some of the broader, comparative issues involved.

The literature on the Arabian Peninsula, and on the Yemens in particular, has expanded greatly since I first began working on this area in the late 1960s. There is now an international community of people writing on this region to whose labours I owe a special debt of thanks, both for the research which they have published, and for the encouragement which the very existence of a wider community of scholars provides. While part of the Arab world, the two Yemens have distinctive characteristics and recent histories that make the analysis of their policies challenging and rewarding. Among these are the relation of social upheaval to foreign relations, especially important in regard to the two Yemens; the tense relations between oil-producing monarchies and the, until very recently, oil-less republics; and the specific impact on the Peninsula of regional issues – not only the Arab-Israeli dispute, but also those of the Horn of Africa and of the Persian Gulf.