Catalogue of the books in the Mostyn Library, interleaved with a catalogue of the books in the Gloddaeth Library (ff. 2 verso-247). The Mostyn catalogue was written in a blank book sometime after 1727, with additions to 1733. The Gloddaeth catalogue, written not before 1733, with additions to 1745, was interleaved in the book by tipping in bifolia with paste and at the same time running thread inside the hinge of each bifolium and down the inside of the spine. The Mostyn catalogue is written on the rectos, leaving blank pages and space between entries for later additions; some later additions are also made on the versos. The Gloddaeth catalogue is closely written on rectos and versos. Both catalogues give titles with places and dates of publication. The Gloddaeth catalogue alone gives pressmarks. Both catalogues in the hand of Thomas Mostyn, 4th bart.
The arrangement is (1) by broad subjects, (2) according to size. The categories are as follows: Libri Theologici (ff. 3-21), Libri Juridici (ff. 25-41), Libri Medici (ff. 44-48), Poetae (ff. 49-50 verso, 63-65), Poetae Graeci (ff. 51, 56-57, 67-68), Poetae Latini (ff. 52-54, 58-61, 69-77), Poetae Italici (ff. 55, 62, 79 recto-verso), Poetae Britannici (ff. 55 verso, 61 verso), Poetae Gallici (ff. 62 verso, 80), Oratores et Epistolographi Graeci (ff. 82-84), Oratores et Epistolographi Latini (ff. 85-91), Oratores et Epistolographi Gallici (f. 92), Oratores et Epistolographi Italici (f. 93), Antiquarii (ff. 95-108), Historia Universalis, Chronologica et Geographica (ff. 110-115), Historia Judaica, Chaldaica, Babylonica (f. 116), Historia Graeca et Romana (ff. 117 verso-134), Historia Hispanica et Lusitanica (ff. 137-141), Historia Italica (ff. 142-146), Historia Gallica (ff. 147-157 verso), Historia Germanica et Regionum Septentrionalum (ff. 154, 159-160), Historia Belgica, Germanica, Danica, Suecica, Relvetica et Russica (ff. 155-157, 174-176), Historia Magnae Britanniae (ff. 161-173), Historia Asiatica, Africana et Americana (ff. 177-181), Historia Byzantina et Turcica (f. 182), Illustrium Virorum Vitae (ff. 185-187), Lexicographi et Grammatici (ff. 189-193), Bibliothecarli (ff. 194-196), Auctores Veteres Classicae Ordinis (ff. 198-207), Grammatici et Critici (ff. 208-213), Philologici et Miscellanei (ff. 217-235), Libri Manuscripti (5 items only) (f. 237), Itineraria (ff. 239-240 verso), Voyageurs (ff. 241-243), Appendix ad Historiam Gallicam (f. 244), Historia Naturalis (f. 245), Appendix ad Historiam Magnae Britanniae (f. 247).