ken meltsner nmeyfuzdalummitedu isbn goes back preupc 1970 became international standard 1974 upc codes go back early 70s appears wikipedia didnt furnish intersection two pieces information publishers start using upcs encode isbns books suspect late seventies although probably wasnt widespreadmandatory big chains started require upcs books sold magazines way given issn international standard serial number believe assigned title individual issue issue may also get isbn thanks always wikipedia info finally ive said elsewhere careful like natural unique identifiers isbns arent perfect primary keys db sense many publishers accidentally reused isbns totally different books failed change assigned number book revised also inconsistent assigning isbns editions sold several countries sometimes end isbn looks like publisher made number waldenbooks demanded one ken meltsner thu 07 aug 2008 020017 0500 fork book mooch