THE PRESENT WORK is the product of teaching and research efforts over more than a decade. The core of it was sketched out in Chapter VIII, Al-Islām wa-l- ‘Arab, of my last major work, Muqaddima Pī al- Tārīkh al-Ākhar (Jerusalem 1984, in Arabic). After the loss of my job in the University of Nablus, West Bank, in the wake of the publication of that book, and some unfortunate personal complications which followed, my research work suffered serious interruptions. However, with the moral support of my colleagues at the Hebrew University, above all that of my teacher, Professor M.J. Kister, and a generous grant from the Truman Institute of the University, I was able to resume my work. For this encouragement I am very grateful. I would also like to thank the administrators of the Fulbright Fund for a two-year fellowship in the United States in 1985-87. My visiting fellowship at Princeton University in 1986-87 was especially fruitfull and enabled me to use the rich and well-organized collections of Firestone Library.

Parts of the thesis in this work were presented at various colloquia and seminars, as well as occasionally discussed with some of my colleagues in private. I have greatly benefited from the reactions and criticism evoked, especially when I presented my concluding notes at the Fifth International Colloquium held by the Institute of Advanced Studies of the Hebrew University of Jerusalem in July 1990. To Professor M.J. Kister, who virtually taught me the art of reading years after my father decided that I should learn it, I owe a special debt of gratitude. I have also benefited from the discussions that I have had with Professors Bernard Lewis and Michael Cook of Princeton University, Joseph Sadan of Tel-Aviv University and Moshe Sharon and Albert Arazi of the Hebrew University of Jerusalem.

But the present work could not have been the same without the endless efforts of Dr. Lawrence Conrad of the Wellcome Institute, London, who read the text and offered important suggestions and corrections that at times resulted in rewriting important sections of it.