An ISBN, or International Standard Book Number, is a unique identifier for books. It helps publishers, booksellers, and libraries easily locate and manage specific titles. Each ISBN consists of 13 digits, which can be divided into different parts that represent the country, publisher, and title. ISBNs are essential for the book industry, as they streamline the process of ordering and selling books. When a book is published, it is assigned an ISBN, making it easier for readers to find and purchase it. This system ensures that each edition of a book is distinct and easily identifiable.