The first edition of this book having been out of print for several years and frequent inquiries having been made for copies, this new edition has been prepared and an effort has been made to revise the work in the light of the fresh materials that have accumulated during the last sixteen years; but I can make no claim to have made myself acquainted with the whole of the vast literature on the subject, in upwards of ten different languages, which has been published during this interval. The growing interest in Islam and the various branches of study connected with it, may be estimated from the fact that since 1906 five periodicals have made their appearance devoted to investigations cognate to the subject-matter of the present work, viz. Revue du Monde Musulman, publiée par La Mission Scientifique du Maroc (Paris, 1906– ); Der Islam, Zeitschrift für Geschichte und Kultur des islamischen Orients (Strassburg, 1910– ); The Moslem World, a quarterly review of current events, literature, and thought among Mohammedans, and the progress of Christian Missions in Moslem lands (London, 1911– ); Mir Islama (St. Petersburg, 1912– ); and Die Welt des Islams, Zeitschrift der deutschen Gesellschaft für Islamkunde (Berlin, 1913– ). The Christian missionary societies are also now devoting increased attention to the subject of Muslim missionary activity and accordingly it takes up a proportionately larger place in their publications than before. This second edition would have been completed several years ago but for the illiberal policy which closes the Reading Room of the British Museum at 7 o’clock and has thus made it practically inaccessible to me except on Saturdays. [5] I therefore desire to express my grateful thanks to those friends who have facilitated my labours by the loan of books from the Libraries of the University of Leiden and the University of Utrecht (through the kind offices of Professor Wensinck), and the École des Langues Orientales Vivantes, Paris;—to Mr. J. A. Oldham, editor of The International Review of Missions, I am indebted for the loan of volumes of the Allgemeine Missions-Zeitschrift, a set of which I have been unable to find in London; my thanks are specially due to Dr. F. W. Thomas, who has allowed me to study for lengthy periods (along with other books from the India Office Library) the monumental Annali dell’ Islam by Leone Caetani, Principe di Teano,—a work of inestimable value for the early history of Islam, but unfortunately placed out of the reach of the average scholar by reason of its great cost. I am also much indebted for several valuable indications to those scholars who reviewed the book when it first appeared,—above all, to Professor Goldziher, whose sympathetic interest in this work has encouraged me to continue it. London, 1913. CONTENTS CHAPTER I. INTRODUCTION. PAGE