There is one register, arranged alphabetically. Each book is provided with a letter signifying the discipline which it belongs to. As follows:
| T | theology and religion |
| (Bible editions, exegesis, Bible geography and archaeology, geographia sacra, apologetics / controversy, dogmatics, christology, theology of morality, liturgy, editions of Fathers of the Church, judaica religiosa / Judaic religious subjects, Talmudic writings, missals / prayer books, psalm-books and song-books with or without music, devotion, sermons, morality / christian ethics, religious pamphlets, devotional stories about saints) | |
| J | law |
| (canonical and civil law, Roman and national law, jurisprudence, natural law, philosophy of law, private law, books of law practitioners, civics, official documents) | |
| G | geography |
| (not ‘geographia sacra’ and ‘geographia antiqua’), journeys / journeys of scholars, ship journals, cartography, town descriptions, land surveying, astronomy, cosmography | |
| H | history, economics, weights and measures |
| (antiquarian and modern history, church history and profane history, coinage, political pamphlets, memoirs, biographies, antiquities, political affairs, theory of history) | |
| P | only real philosophy and history of philosophy |
| (history of philosophers and history of philosophy, metaphysics / ontology, logic, philosophia naturalis, ethics, theologia naturalis) | |
| S&M | science, medicine and engineering |
| (mathematics, experimental physics, chemistry, alchemy, biology / botany, agricultural and horticultural science, hydrolic engeneering, medical science / pharmaceutics, building of fortresses, weaponry, military science, real economics of numerals and percentages) | |
| L | arts, art |
| (dictionaries, rhetoric, grammar / etymology, antiquarian and modern philology, orationes (Francius), geographia antiqua, literary aesthetics, literatures of the antiquity, modern literature of all languages, art of painting, sculpture, aesthetic architecture, iconology, books like Les Mots à la Mode by Callières, bibliografies like those by Van Berghem, Scaligerana and such) | |
| Pd | pedagogics (e.g. Locke) and didactics (e.g. Antonius Schorus) |
| D | various subjects, miscellaneous |
Sometimes more than one letter is needed.
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