This thesis presents a critical edition of the Ihya al-Sunna wa-Ikhmäd al-Bid'a of 'Uthmän b. Füd!, the famous Muslim Reformer of the late 18th and early 19th centuries in West Africa. In comparison with all his other known works, over a hundred of them, this book occupies a pride of place and is evidently the author's most major work on Islamic theology and law. The principal parts of the thesis comprise an introduction which consists of four chapters; the text of the book in Arabic; notes and commentary based on the text; and an appendix. Chapter one of the introduction gives a brief account of the author's background : his racial origin and the environment in which he lived. The second chapter treats of his life, career and eventual holy war. Chapter three deals with the author's works in two parts. The first part describes the six manuscripts from which the text has been collated, and the second part gives a complete list of all the author's known works; and also indicates where the manuscripts of most of they.. can be found. Chapter four gives an exposition of the contents of the present work and its importance, and also includes a full translation of the author's Conclusion. The text consists of a preface, an introduction, thirty-three chapters and a conclusion. Footnotes in the text give the variants met with among the manuscripts. Historical and literary glosses are included under Notes and Commentary which also include references to the principal works quoted in the book. A chronology of events in the author's life is given in the appendix.