Mapping Early Modern Quiring: Data Mining the Anet Database of Hand Press Books Tom Deneire Special Collections, University of Antwerp Library Tom.Deneire@uantwerpen.be last revision: 28 June 2017 Abstract This paper documents the methodology used to digitally map early modern quiring patterns through the analysis of a corpus of bibliographic metadata about hand press books from the period 1471-1861. It describes the application of an algorithm that registers the presence of a certain quiring and the ensuing results, mainly relating quiring to chronological (century) and bibliographic factors (format). In conclusion, the interpretation and future analysis of these results for the study of book history is discussed. 1. Definition As a preliŵiŶary Ŷote, it will ďe useful to rehearse how Gaskells ŵaŶual oŶ ďiďliography defiŶes quiring as part of handpress book production: It was normal in the early days of printing to impose [sc. sheets] for gatherings of several sheets tucked, or quired, inside each other. Thus a folio gathering might consist of three folio sheets [i.e. three sheets folded once], the outermost of which contained pages 1 and 12 (printed from the outer forme) and pages 2 and 11 (from the inner forme); the middle sheet had pages 3 and 10, 4 and 9; and the innermost sheet had pages 5 and 8, 6 and 7. All three sheets were signed with the same letter (A1 on page ϭ, AϮ oŶ page ϯ, aŶd Aϯ oŶ page ϱͿ, aŶd the foldiŶg is desigŶated Ϯ° iŶ ϲs (GASKELL 2012: 82) 2. Methodology The starting point for this research was an XML export (31 May 2017) through Brocade (version 4.20) of the Anet 1 database of catalographic descriptions of book editions. Only handpress book editions were exported from the database, i.e. all records that have RECORD/BSECTION/LM/@lm=”od”. These catalographic descriptions employ a specific XML-scheme, of which the following record is an example: 1 Anet is a library network in Belgium hosted by the University of Antwerp. Brocade Library Services is a fully integrated web-based Library Information Management System, developed by the University of Antwerp in 1998. Cf. https://en.wikipedia.org/wiki/Brocade_Library_Services and www.anet.be.