The book is concerned with a study and critical examination of the manuscript al-Du afa of al- Bukhari, one of the earliest and most important manuscripts to be written on the subject of al-Jarh & al-Ta dil. The book is one of the first to examine existing manuscripts of this work, and in it five copies of the same manuscripts are compared. It is one of few studies in English that critically examine the books of al-Jarh & al-Ta dil, to try to understand the methodology of its scholars, and to attempt a reconciliation between their differing opinions. The book considered to be an exposition of one main point; it collatescollates and critically examines the terms of Al-Jarh that have been used by al-Bukhari or transmitted by him from his teachers, and a comparison of his usage of these terms with other common opinions regarding them. Also, a comparison is made between al-Bukhari s usage of these terms in this manuscript with his usage in his other books. This study makes apparent the great importance of the manuscript al-Du afa in this field.