Understanding book serial numbers (SNs).

Explaining what a book serial number is, how its created and why it's useful. (LIBRARY)

Book SNs come in two parts.

The first 13 digits are a number that is derived from the title of the book (For the nerds, its a SHA 265 hash of the title, as seen exactly in the title field.).
the second four characters are a randomly created series of letters and numbers. These are used to separate one physical title from another. If a library had tow copies of "The Princess and the Goblin", both would have the prefix "2462791569705", but the suffix would be different; "2c6b" in this case.

Originally this was gong to be a unique identifier for allowing libraries to federate, but the structure of Pibliotheca has since shifted away from that model.