Codex Casanatensis Ms. 1730 is a compendious work containing a wide assortment of texts related to the medieval inquisition. This codex was conceived and executed as an unitary whole, and produced in the early fourteenth century for Franciscan inquisitors in Tuscany. While many texts in Casanatensis 1730 appear in other inquisitors’ codices, there are also texts that are unique to Ms. 1730. Among these is an index at the start (fol. 1-37) that not only covers Casanatensis 1730 in its entirety, but also contains features that render it especially utilitarian. Through an exploration of these unique features in the index of Casanatensis 1730, it appears that in the index alone, an inquisitor had at hand an alphabetically-arranged mini-libellus that comprised thirty-seven folios of a work that ultimately contains 297 folios, and that set forth his duties, powers, procedures, possible penalties et al. The index was composed in a form that was not only a summary of authoritative lengthy legal texts in the codex, but one that was easily accessible, consultable, and portable. Casanatensis 1730 was never intended to be read from beginning to end. It was an early inquisitorial legal reference work with encyclopedic contents, but those very same contents were reduced to index entries, which are brief summaries, to which inquisitors could quickly and easily refer. The index of Codex Casanatensis 1730 was the medium by which a complex body of legal texts was reduced to its essentials, and re-arranged into a form that could be accessed quickly and easily by anyone in need of such a handy reference guide; thereby expediting the inqusitorial process and better enabling an inquisitopr to “Statim prosequi…immediately prosecute”.