Literary genres or subgenres may experience a rise in importance and public interest, a decline, and sometimes periods of revival. Studying such trends is part of the field of the History of the Book. This modern field of historical inquiry is interested in tracking books as objects and as socio-historical agents. In this paper is interested in applying some of the field’s concepts and techniques to a subgenre of medieval Islamic books, namely ‘Aqida books. What links these books to modern ones and enables us to use the same techniques and concepts on both is the fact that in the Islamic empire after the mid-eight century there was a real industry of the book accompanied by a real market where books, as intellectual and industrial products, are traded and consumed. The special edition of JAIS titled The book in fact and fiction in pre-modern Arabic literature (Ghersetti, Metcalf eds, 2012) is a great attempt at launching the subfield of the history of the medieval Islamic book. The volume marks a departure from the earlier trends of bibliography (Sezgin and Brockelman); introduction to the medieval Islamic “book milieu” (Perdersen, The Arabic Book); surveys of the development of a literary genre such as the development of Islamic historiography (Humphreys in EI2; Robinson and others); or the development and canonization of Hadith compilations (Lucas and Brown). R. Darnton describes the book industry as an integrated “communication circuit” that includes “authors, publishers, printers, shippers, booksellers and readers”; all immersed in powerful economic, commercial, social, legal, and political force fields. In the current paper we trace the work of the combined elements of the communication circuit to produce and propagate ‘Aqida books (or “doctrine”; a subgenre of Islamic dogma and theology). We will follow the rise and decline of this subgenre, its main authors, the pivotal points in its history, and the social, political and intellectual currents that made this subgenre possible, shaped its content, and allow it to exercise a certain historical agency. We foresee this agency to be the crystallization of Sunnism and the Shiism as separate branches of Islam, as well as separate and antagonistic communities. We foresee the peak points of production in this subgenre to coincide with the period of heightened tensions between communities and kingdoms that adopted these two doctrines; namely the Buyid period in Baghdad and the Fatimid period (and its Ayyubid aftermath in Syria and Egypt).