ISBlogN

The Millions (A Blog About Books) writes about the 13-digit ISBN transition. By 2007, the 10-digit ISBN (nine real information digits and one checksum digit) will be replaced by a 13-digit ISBN (3-digit prefix, 9 info digits, 1 checksum digit), which will be identical to the current 13-digit BookLand EAN but starting with 979 instead of 978.

C. Max Magee explains that there will be some real transition issues for smaller booksellers who have to convert legacy systems. On the other hand, I've been told by a lot of the bookseller aggregator sites--ones like Alibris and ABEBooks who entirely or largely list books from independent booksellers--that most of the stores use one of a few inventory management packages. (Hey, so all the online booksellers have to move to using EANs primarily, too; some allow them now.)

The 978 prefix, which identifies a mythical country in the EAN worldspace called BookLand, allowed ISBNs to be freely converted into internationally compatible EAN systems. More confusingly, the US has been using a 12-digit UPC code in retailing which is transitioning to the full 13 digits for better globalization.

(Mark of the Beast theorists, start your biblical engines!)

It's an expansion of the namespace for ISBNs, too, because all existing ISBNs will be honored in the 978-prefix namespace forever. Publishers with existing ISBN inventories can continue to use them by converting them into the 978 system. New ISBNs will be assigned as a complete EAN number starting with 979 and will not be convertible back to the old 10-digit system. This opens 1,000,000,000 new ISBNs for assignment, just incidentally, since the two namespaces (978 and 979) will be independent.

Here's the U.S. ISBN authority's explanation.

Magee's site is worth reading for any inside-baseball bibliophile.