Book excerpt: The sciences of narrators and narrations (rijal and dirayah) are among the most fundamental fields of study that a mujtahid must master as part of his expertise of ijtihad. They are very detailed and technical subjects, each with its own rich history of development. In this book, the author expertly presents an introduction to these subjects and discusses their main topics in the form of thirty-four lessons. Each lesson concludes with a series of questions in the form of exercises to test the comprehension of the reader. The first half of this beginner's guide acquaints the reader wtih the key questions of the study of the narrators of hadith, including the reliability of a narrators, the narrations by the companions of the Imams, and an explanation of rijali terms and phrases. This section addresses internal debates over the efficacy of biographical studies and explores whether certian narrators can be considered absolutely reliable from within the Shi'i tradition. The second half delves into the classification and evaluation of hadith, including authenticity, the traditional methodologies of transmitting hadith, and the approaches scholars take in the face of seemingly contradictory evidence regarding the reliability of a narrator or a hadith. All in all, this book is an excellent introduction to the traditional study of traditions, particularly in the Twelver Shi'i heritage. It will leave the serious student well equipped to proceed in scholarly traditional studies of narrators and narrations.