ISBN Textbook - the Dewey Decimal System of the Bookworld

Believe it or not, the ISBM system is about others being able to identify and locate a specific book.
The International Standard Book Number system is supported by the publishers. The whole intent is to be able to identify a title or edition of a specific title from a particular publisher. This makes it easier for libraries, bookstores, and other parts of the book and textbook distribution system to locate the books or inventory they need.

So while we may consider the ISBN system a good way to identify a book, it's initial design wasn't for the benefit of the consumer.

The ISBN textbook and other manuscript number consists of 4 parts.

Group or country identifier. - Where it's published geographically
Who is the Publisher
Title Identifier
Check Digit to validate the ISBN number

There are over 160 agencies that can issue an ISBN number. They are exclusively responsible for assigning the numbers to publishers based on a specific country or geographic area.

These ISBN textbook numbers also help us consumers to get the right book. Many revisions and editions of a specific book have been known to make changes that may or may NOT include a sub-title, etc. This in turn could cause confusion on which book you actually want to find. By using a standard ISBN number, you are assured of "talking the same language" as the book distribution channel. This channel includes not only the publisher but also the distributor, wholesaler, and retail bookstore.