A numbering system is increasingly important in the digital age when it comes to getting paid.

Back in the Olden Days when there was a Sam the Record Man in every mall, you might remember a massive looseleaf book that lurked somewhere in the store.

Locked on a metal stand and filled with bright coloured pages (yellow, orange, pink) covered in what must have been a four-point font, it was a catalogue of artist, titles, labels, and matrix numbers of hundreds of thousands of recordings. If the store didn’t stock what you were looking for, you’d head for The Book, find what you needed and then have it special ordered.

As far as anyone was concerned, The Book was a printed database of the entirety of humanity’s music. It seems both mysterious and wondrous.

Bookstores had something similar. In 1970, a standard was created to give every book a unique identifier: an International Standard Book Number (ISBN). All books come with a 10- or 13-digit number somewhere on or inside the cover. Each edition and each variation has its own number. The hardcover, the paperback, and the e-book have separate IDs. If you need to acquire a copy of a book, it’s as easy as going to the ISBN Database and launching a search.

If this has been done for books, then it certainly must have been done for music, right? Surely someone must have found the 21st-century equivalent to that big book at Sam the Record Man.

Well, no. At least not entirely. And it’s complicated.