The paradigmatic public institution associated with the application of Islamic law from the rise of Islam until the end of the nineteenth century has been the qadi. This essay examines the scholarship on this institution, organizing studies into doctrinal works and empirical works. Doctrinal studies of the qadi are based almost entirely on literary sources, most commonly legal texts. Historical sources have also been important, especially for the pre-Ottoman period. Empirical studies of the qadi, by contrast, base themselves almost entirely on surviving court records. Thus, most empirical studies are limited to courts of the Ottoman Empire which kept systematic records of court decisions in contrast to the courts of previous Muslim states, which did not. In the modern period, there has been a distinct rise in an anthropological approach to the qadi, with numerous studies having been published based on direct observation of the behavior of Muslim judges.