Abstract: This Article studies the legal position of the muhtasib in medieval Cairo, using the biographical information available about the individuals who held the position to understand the actions they took in office. The muhtasib, who was an inspector of public places and markets in particular, was a key legal actor in terms of applying law immediately to a situation he encountered; he was a common face of the law in society. This Article, influenced in method by legal realism, shows that in addition to the law that a particular muhtasib intended to apply to a particular case, biographical information is crucial in explaining how and why each muhtasib responded to particular events.