If you want to know more about the International Standard Book Number, go visit this web page. It especially tells you what elements the ISBN is made up of besides its history and facts.
This is a free website that allows users to search for books not only by the title or author, but by ISBN numbers.
I found this helpful for when textbooks are hard to find. Instructors usually provide the ISBN numbers in their syllabi and this is one resource a student could use to locate out-of-stock books.