For those with an interest in understanding the evolution of Judaism in the Islamic lands of the Middle Ages, but not necessarily with a specialized knowledge or training as historians, it is necessary to offer a few general words of warning about the nature, variety, and exploitation of the sources from which history is derived. Though now virtually axiomatic for those who research and write about the past in a scientific fashion, such cautions need to be sounded because there are still approaches to the history of medieval religion – perhaps particularly to that area of study – that may, at least sometimes, take it for granted that the circumstances, personalities, and interpretations that are noted in the early and traditional texts of a faith community are to be understood literally. The reality is that what is reflected in such data is not only a view on a particular period but also the notions and commitments of their chroniclers. History is lived forward but written backward so that all assessments have more than a small element of hindsight and bias.