Isbn numbers for textbooks ?

i am searching for textbooks and finding that many books dont have matching isbns when compared to the list the school gave me. the are the same authoir, book, edition, cover,etc. is it safe to by the same title and author, edition and publisher, even if isbn doesnt match?|||Unfortunately not. The only way to be sure that you have the exact same textbook as what is required for your class is to match the ISBNs exactly. Most online vendors should allow you to search by the ISBN to find the correct item. You may also notice that some of the books you find have a different last digit, the check digit which is an exception to the rule. A book with the exact same ISBN except for the last digit is the same book, just usually published by a different company. There are two versions of ISBNs available, ISBN 10 and ISBN 13. Every book has both, but usually ISBN 10 is the same as the ISBN 13 just without the first three numbers. If your school uses custom editions, you may have a hard time finding the materials anywhere else but you should definitely consult your professor if that is the case.