The Smithfield Decretals (British Library, Royal MS. 10 E.iv) is an exceptionally large (c.450 x 285mm.) and lavish (including more than 600 narrative bas-de-page scenes) copy of the Decretals of Gregory IX with the gloss of Bernard of Parma, thought to have been written in southern France c.1300, with decoration and an extra prefatory quire added in England some decades later.
The main reason I found fault with a recent monograph on the Taymouth Hours is that it tends to treat hypotheses as facts. One of several such hypotheses is the proposal that the Smithfield Decretals was made for man called John Batayle who was a canon of St Bartolomew's, Smithfield, in the last quarter of the 14th century. This may be true, or it may not.
I occasionally encounter catalogue descriptions which mention an anonymous bookplate, variously described by different cataloguers, but recognisable from its device/motto on the scroll below the shield "EXCELSIOR":
Baltimore, Johns Hopkins University, John Work Garrett Library, Gar 6 http://www.digital-scriptorium.org
Anyone not familiar with Count Guglielmo Bruto Icilio Timoleone Libri-Carucci dalla Sommaia (1802-1869) will have no trouble finding biographies online, including Wikipedia's. The title of his full-length biography gives a good indication of the reasons for his fame and notoriety: P. Alessandra Maccioni-Ruju and Marco Mostert, The Life and Times of Guglielmo Libri (1802-1869), Scientist, Patriot, Scholar, Journalist and Thief: A Nineteenth-Century Story (Hilversum, 1995).
The catalogue of the Libri Collection of the 4th Earl of Ashburnham is online: A Catalogue of the Manuscripts at Ashburnham Place: Comprising a Collection Formed by Professor Libri (London, [n.d.])
The auction Catalogue of the Extraordinary Collection of Splendid Manuscripts, Chiefly Upon Vellum, in Various Languages of Europe and the East, formed by M. Guglielmo Libri, the Eminent Collector, who is Obliged to Leave London in Consequence of Ill Health, and for that Reason to Dispose of his Literary Treasures ... which will be Sold by Leigh Sotheby & John Wilknson ... Monday, 28th of March, 1859, and Seven Following Days ... is available online in at least four different copies:
A partially annotated copy of his sale catalogue: Catalogue de la collection formée par M. Didier Petit a Lyon ... Paris, Dentu, au Palais Royal, (1843), is available through Gallica, and an unannotated one through Google Books.