Tags

, ,

Dear Kelsey,

Did you know there’s a way to compress every published work of literature—no matter how long or complicated—into a short string of numbers? And that, once compressed, the reader can still extract the original form?

Of course you do.

ISBNs are not new—the technology has been around for decades—but what is news (at least for me) is that they’re actually really interesting.

I’ve always been under the impression that ISBNs were randomly generated 10- or 13-digit codes that identify a particular book. But while ISBNs do indicate a particular book, don’t mistake them for a random string of numbers.

ISBN What Explanation Explained EAN GS1 prefix Check code title publisher 978 979 13-     ISBN What Explanation Explained EAN GS1 prefix Check code title publisher 978 979 13-

a: 978 and 979. The first three numbers of an ISBN refer to GS1/EAN number. GS1 (formerly known as EAN International) is an international nonprofit association for the development and implementation of supply chain standards. One of the biggest things they do is supply standardized barcodes to identify products worldwide. The GS1 number in an ISBN refers to the industry of the product: 978 and 979 prefixes indicate Book Publishing and are reserved solely for book identification.

b: 0 and 1. This number reveals the country/language the book was published in. 0 and 1 indicate English language books. The number of digits here is not fixed, however; if you’re reading a book from Botswana, the country code is actually 5 digits long.

     

c & d: Combined, these two parts will always total 8 digits (for books in English). The numbers are split between the Publisher Code (c) and the Title Code (d). 

c: This indicates the Publisher Code. Don’t get too excited, though; the way ISBNs are registered prevents a publisher from having a single, trackable code. Publishers receive a “block” of ISBNs (at Paradigm, they’re actually stored in a binder) which they fill at their own pace. Once they’ve used the available ISBNs in the block, they get another block of ISBNs and a new publisher code. Smaller publishers often receive longer publisher codes (as in the examples below), giving them fewer product numbers available for their titles, whereas big publishers will receive smaller publisher codes (as above) to allow them to register many more titles under the same code. 

d: This indicates the Title Code. Shockingly, this is the only unique part of the ISBN, allowing you to identify the book. 

e: Check Number. The last number of the ISBN exists solely to catch errors. Since it’s common to mistype or transpose numbers in a long string, the check digit simply verifies the accuracy of the entry. Using a formula, it’s actually possible to figure out the check digit without knowing ahead of time. And in fact, when registering barcodes, our program does predict the check number as an additional verification. To figure it out yourself, the calculation is as follows: Using only the first twelve digits of the ISBN (excluding the Check number itself), multiply each digit from left to right by 1 then 3, alternating down the line, and add them together.

(9×1 + 7×3 + 8×1 + 0x3…and so on)

Then, divide the total by 10 in the old fashioned “remainder of” style (in other words, not into a decimal or fraction). The remainder is subtracted from 10 and the result (with any 10s becoming 0s) is the check number.

…thus endeth the lesson 🙂

Love,

Maggie

Advertisements