This document, known in Orientalist jargon as the "Constitution of Medina," is accepted, even by iconclasts of the field, as an original document going back to the Prophet Muhammad. Yet, for some reason, it has not received its fair share of scholarly attention. This book is an attempt to remedy this situation, and includes the two known versions of the "Constitution," founded on many sources. This is followed by introductory chapters dealing with the Muslim and Jewish groups that participated in the document. Finally, there is a translation and a detailed commentary on the clauses. In this book, the author argues that most of the Jewish tribes of Medina, including the large ones, did not participate in the "Constitution"; the main tribes had more rudimentary, non-belligerency treaties with Muhammad. In addition, the assumption that the "Constitution" declared each Jewish group as an umma or community rests on a faulty reading: In fact the participating Jews received a guarantee of security (amana). This monograph will enrich the resources available for the study of Muhammad’s concepts and policies shortly after his arrival at Medina.