“De pentagono Salomonis, Ars loquendi et intelligendi in lingua hebraica, De rebus metallicis by Roger of Hereford, Algebra by Al-Kuwarizmi, translated into Latin by Robertus Anglicus, the Punica of Silius Italicus, the Gesta francorum, De laudibus sanctae crucis by Rabanus Maurus, and Flavii Claudii Giordani de aetate mundi et bominis reservatis singulis litteris per singulos libros ab A usque ad Z,” my master read. “Splendid works. But in what order are they listed?” He quoted from a text I did not know but which was certainly familiar to Malachi: “‘ The librarian must have a list of all books, carefully ordered by subjects and authors, and they must be classified on the shelves with numerical indications.’ How do you know the collocation of each book?”

I'm pulling out this particular quote partly because it's a great example of something that looks like local colour but actually turns out to be fundamental to the plot, but mainly because it has a reference to Roger of Hereford, the medieval scholar on whom I was once an expert. Oddly enough – and Eco surely cannot have known this – De rebus metallicis by Roger of Hereford has completely vanished, if it ever existed. It was listed (as expoſitiones magiſtri Rogeri de Horeford de rebus metallicis) as being at the library of Peterhouse in Cambridge by John Leland somewhere around 1535, but is not otherwise recorded. Myself I think Leland (or quite possibly Thomas Tanner and/or Thomas Hearne, who transcribed Leland's notes, which themselves are lost, for publication in the 18th century – they may even have been working from an earlier transcript made in the 1570s by John Stow) misread the name of the author and slightly truncated the name of the book, and it was actually De mineralibus et rebus metallicis by Albertus Magnus that Leland saw in Peterhouse. It is not recorded in the list of books borrowed by Dr John Dee from Peterhouse in 1556, but I guess he might have nicked it anyway (or in fairness anyone else could have done so). Given the extent to which Eco raves about Albertus in the introduction to The Name of the Rose, I think this notion would please him. Wiiliam of Baskerville and John Leland are the only people ever recorded as having direct knowledge of the book, one in a novel published in 1983, the other in a hand-written note published two hundred years after he died insane.

This moved me to look also at the other books mentioned.

• De pentagono Salomonis turns up again in Adso's dream on the sixth day, and it's a reasonable variant title of a well-enough known text normally called Pentaculum Salomonis.
• Ars loquendi et intelligendi in lingua hebraica is also a fairly well-known title, though I suspect it may cover more than one text.
• Algebra is the most famous of these books; it gave us the word "Algebra", and its author's name gave us the word "algorithm". The 12th-century Englishman who first translated it into Latin (and invented the term "sine" by accident) is usually referred to as Robert of Chester these days, to avoid confusion with the 13th-century Robertus Anglicus who wrote the first ever description of a weight-driven clock in about 1280.
• The Punica of Silius Italicus is available from Loeb in two volumes.
• The Gesta Francorum is available in English translation.
• De laudibus sanctae crucis is one of Rabanus Maurus' better known works.
• The last entry puzzled me for a bit though. "bominis", clearly there in my Kindle edition, is an obvious mistake for "hominis". That led me to this reference to a book with the same title but the author's name spelt with a couple fewer letters. Armed with that, I discovered that the author's name is probably wrong anyway and Wikipedia has this note on the book, which consists of successive volumes each of which is written without using a particular letter, a, b, c etc.

So of the books there are three scientific/magical treatises, three histories, a Hebrew textbook and a religious poem. I don't know what to read into that.

It does strike me, looking again at the introduction, that the story of Roger of Hereford's lost De rebus metallicis above is not all that different from Eco's own (fictional) account of his attempts to track down the story of Adso of Melk after losing the original version. Perhaps he knew after all?

And one last thing – the incorrect letters in Eco's rendition of the last book's title, "Flavii Claudii Giordani de aetate mundi et bominis reservatis" are the L in "Flavii", the first I in "Giordani" and the B in "bominis". Those are the first three letters of "liber" and "libro", the Latin and Italian words for "book" (hence the English "library", though in fact the Latin and Italian words for library are Bibliotheca/Biblioteca from Greek Βιβλιοθήκη). Maybe I'm reading too much into it, but if so, it's a nice coincidence.