Insight into the mind of Ben Franklin is the hopeful outcome. Franklin historians follow a lead on shelf marks in order to amass a list of the 4,276 books in his library.

The volumes were listed by “Case” and “Number,” leading Mr. Wolf to conclude that the shelf mark referred to the location of the books on Franklin’s shelves at home. The C stood for case and indicated on which shelf the book belonged, while the N stood for number, referring to the position of the book on the shelf.
By the time he died in 1991, Mr. Wolf had deduced about 3,000 titles contained in about 1,000 volumes, or about a quarter of Franklin’s library. He also had identified the names of about 700 books Franklin had mentioned owning in his letters, though actual copies have not been located yet.

Now that information, along with some additional research, is being codified by researcher Kevin Hayes in a 900-page bibliography of 3,741 titles comprising about 2,000 volumes. Included in the catalog are works such as a 1764 edition of “Two Treatises of Government,” by John Locke; a 1721 edition of “Opticks: Or, a Treatise of the Reflections, Refractions, Inflections and Colours of Light,” by Isaac Newton; and a 1556 edition in Latin of the Magna Carta, one of the world’s most important political documents.

Imagine spending the bulk of your life hunting down the titles of someone else’s library. It’s the most gorgeously geeky thing I’ve ever heard of.