Yes, Bookshare does a checksum on the ISBN number. I just found a description of the algorithm at http://wiki.tcl.tk/12638. I happen to know the checksum algorithm for credit cards, but not for ISBN numbers. Probably the OCR program flipped a digit during its processing. Just checked on amazon.com - the 2nd 9 should be an 8, so the correct ISBN is 0-394-84193-X. HTH, Carrie ----- Original Message ---- From: Karen Harshfield <karenh@xxxxxxxxxxxxxxxxx> To: bksvol-discuss@xxxxxxxxxxxxx Sent: Sunday, September 21, 2008 10:58:47 AM Subject: [bksvol-discuss] ISBN dilemma and questions Hi y'all, I have been trying to submit a book this morning. It's: Joel and the Great Merlini by Eloise Jarvis McGraw The book's copyright page lists two ISBN numbers ISBN 0-394-94193–X ISBN 0-394-94193-4 lib. bdg. (the second number is for library binding) BUT the dual number thing isn't my question. I am entering the first ISBN number on the submit page, and I am getting rejected as having entered an invalid ISBN number. I have cut and pasted it from the scanned book, typed it in by hand, and tried it without the hyphens. No good. Bookshare says it's invalid. I have looked this book up on www.isbndb.com, and have found that the first number is not listed. This website database has it listed with one digit different. I have double checked the copyright page in the book, and the book is different from the web site. I guess my question is: What does the bookshare submit page do to validate the ISBN number? Does it look it up somewhere? Or is some kind of checksum used? Yes, I could take the easy road, and use the second (library binding) ISBN number. But my curiosity has been peaked. - Karen To unsubscribe from this list send a blank Email to bksvol-discuss-request@xxxxxxxxxxxxx put the word 'unsubscribe' by itself in the subject line. To get a list of available commands, put the word 'help' by itself in the subject line.