ISBN, or International Standard Book Number, provides a unique identifier for books and similar products published anywhere in the world.
If a publisher issues a book in both soft cover and hard cover, each will have its own ISBN. So would any large print edition, electronic version, etc. But the publisher does not assign the numbers. ISBN is an international standard, and there are more than 160 ISBN Agencies that have exclusive responsibility to assign ISBNs in a particular country or geographic area.
Why does it matter for anyone who is not somehow in the book business? Because you can use it to search exactly what you are looking for.
Brief history of ISBN
A retired Irish statistics professor devised a 9-digit code called the Standard Book Number in 1966 for the British bookseller W.H. Smith and others. They used it for internal inventory control. It also became a handy stock number and, as computers took on more and more back-office tasks, a number that publishers, retailers, warehouses, and other components of the book industry could use to communicate.
It worked so well that the International Organization for Standardization adopted it (with a tenth digit added to the front) as the International Standard Book Number in 1970. For various reasons, the number was expanded to 13 digits in 2007. Similarly, there are International Standard Serial Numbers (ISSN), International Standard Music Numbers (ISMN), International Standard Recording Codes (ISRC) and more.
Using ISBN for search
Whether using a search engine or a database such as a library catalog, if you are looking for a particular item, it can be difficult to identify it in a large list–particularly if you can’t sort it. In both search engines and library catalogs, searching for a known item by author and title can present difficulties. You can find exactly what you want with the ISBN.
Why would you want to search by ISBN? For one example, say you want to compare prices of a particular book (and specifically, say, paperback) at various online sites. Searching by ISBN brings up records for exactly the same edition of the same title. If you perform each search in a different tab, you wind up with each site’s page for the item in a different tab. That makes them easy to compare.
Knowing the ISBN can also distinguish between different editions of the same title. Publishers issue new editions of college textbooks every few years. If you want a used copy, you’d better make sure you’re getting the same edition the professor has assigned. You must know the correct ISBN and search with it if you want to buy online.
How do you find the ISBN in the first place? You can’t search with what you don’t know. For one thing, whenever you find a listing for the book you want using any search, The ISBN will probably be there. You can simply copy and paste it for whatever other searches you want to do.
There are also any number of web sites where you can look up ISBNs and find as many as you want. And don’t worry about the change from 10 to 13 digits. Other sites easily convert one to the other. On some sites, a library catalog being one, you can search on either number and find your title.