With few exceptions, medieval Islamic literature shows little curiosity regarding non-Muslims. The Jews of northern Arabia, especially those who lived in Medina (pre-Islamic Yathrib), are a prominent exception, due to their role both as supporters and adversaries of the Prophet Muḥammad. The huge medieval literary output about Muḥammad provides many details about them. The details are often problematic, but they are by no means impenetrable. In any case, one’s expectations must take into account the limitations imposed by the very nature of the source material.