Chapter 1 introduces the topic of investigation by explaining the research problem and the state of the art. It shows how some modern scholars believe that classical Muslim sources include scarce information on conversion and consider them the wrong sources for studying the phenomenon. Drawing straightforward links between historiographical reports and events which may have happened centuries earlier is problematic, especially in the absence of actual documentation. However, it is important to study conversion depictions in early Islamic historiographical accounts. Through analyzing a vast number of Arabic Muslim historical accounts, historiography reveals a great deal about conversion. The chapter explains the theoretical basis of the investigation and the methodology of marrying history and historiography by tracing the interplay between historical phenomena and historiographical depictions; external evidence is investigated, then internal criticism is applied. The chapter lists the conversion themes detected, lays out the major arguments of the investigation, and explains the research plan and the outline of the book.