An examination of the structure of the Fihrist reveals a number of principles of organization on which Ibn al-Nadim drew in compiling and arranging his work, chief among which is that of chronology. A close reading of the fifth and sixth maqamacr;las of the Fihrist, dedicated to Islamic theology and law, respectively, indicates that they present not only a taxonomy of the theological and legal schools in Ibn al-Nadimiacute;s environment in Baghdad during the Buwayhid period but also chronologically arrange histories of the foundations of those schools of thought. This original conception is one indication of the value of the Fihrist as an intellectual history of the first four Islamic centuries from the point of view of an Imami Shiءi, Muءtazili thinker.