Book excerpt: First Published in 1980. An important waterway for international trade, the Red Sea is about 2000 kms. long and generally between 200-300 kms. wide. In its southern part the Arabian peninsula approaches the Horn of Africa to a distance of about 25 kms. This book is partly the outcome of research for the chapter called 'Ethiopia and the Horn of Africa' (from the middle of the sixteenth century until the middle of the eighteenth century), published in the fourth volume of the Cambridge History of Africa. The extensive research conducted for several summers between 1967 and 1971 for a forty-page chapter resulted in substantial material in order to create this volume.