Josef Horovitz (1874-1931) wrote this classic monograph a century ago in two parts in German. The editor added footnotes, corrections and the preface, and it is now a book in its own right. The translation was prepared by Marmaduke Pickthall (d. 1936). Lawrence I. Conrad, who re-edited the articles also presents a slightly corrected textual version, expanding and updating the notes and bibliography and adding a new introduction dealing with Horovitz's and other orientalists' work on early Islam in the early 20th century. Horovitz deals with thirteen early scholars who transmitted traditions or.