**The International Serial Book Number was invented in 1965.**

Originally it was nine digits long. Then it became ten. In 2007, it expanded to a sequence of 13.

What* is* this sequence of numbers? A product identifier, used by publishers, booksellers and libraries for ordering, listing and stock control purposes. Through the ISB number the book can be tracked down and, if it’s in print, or in a library, a copy can be obtained.

You can publish without an ISBN, of course. But if you want people to be able to *find* your book, both during its lifetime and in libraries after we’re all long gone, an ISBN is a handy thing.

Publishers buy these numbers in blocks. You can’t buy them individually. In 2005, when I began Happen*Stance* I bought ten, which is the smallest number you could (and can) purchase at one go. They were dead cheap. I don’t recall the exact cost but I think it was less than £1.00 per number. Since then, the price has gone up.

Ten ISBNs currently cost £126.00. One hundred cost £294.00. A thousand cost £774.00.

Anyway, I got my first ten in 2005. Quite quickly after that (a year or so later) I bought a hundred and they cost something very close to a hundred quid. One hundred! That seemed a *huge *number to me at the time.

I’ve just come to the end of that hundred numbers and I’ve bought another hundred. I did consider buying a thousand but . . . I’m sixty. One can only do so much in a lifetime.

There’s little poetry in a list of numbers, it seems to me. However, I found it oddly moving when I realized that the first ISBN in my last hundred was Tom Duddy’s pamphlet *The Small Hours*: 978-1-905939-00-8.

The *last* number of that same block is 978-1-905939-99-2. It belongs to Tom Duddy’s posthumous volume *The Years*. I’m finalising this book for print right now. More about Duddy, and much else, soon.

The 9# and 10# isbns work on an modular mathematical system – where each number multiplied by its relative position and all those added up can then be divided exactly by the modular number, ie 9 or 10 in these cases. When i used to hand bind books some years ago i used a mod12 system for my own id numbers; just for fun really, and because i like maths; but i don’t see why any publisher couldn’t do the same and have their own set of numbers on their own system, and then the book sellers could either use that code or not. Actually, i do see why, i just don’t agree you should have to pay for numbers. Numbers don’t belong to anyone. Might as well sell you an allotment plot on the moon. Though i appreciate the isbns are somewhat more useful.

Very interesting. I can see why [i]I [/i]couldn’t do the same though: I have no maths brain that would compute it.

But I don’t think the numbers, in this case, [i]exactly[/i] belong to anyone. They’re selling the use of them as unique identifiers, aren’t they? and there has to be an agency to check that they remain unique by cross checking each time a book is registered (I have made a mistake more than once and they do notice and tell you). The isbns generate the bar code also, though perhaps if you were clever with numbers you could do that too. It’s Greek to me.

I haven’t bought an allotment plot on the moon yet, though I believe it has been known…