Just thought I'd let you know that we've put up a new version of the ISBN database. We've done a lot of work to pull works with variant titles together (which helps with The Innovator's Dilemma) and made the retrievals consistent, so that any ISBN in a group retrieves that same ISBN group (which also helps with I's D). We've learned a lot about how ISBNs are used (and misused).
Thanks for the update, Thom. Sure enough, my original examples now work as advertised. Here's what Thom was referring to:
There are a few caveats here. First, the one-to-many algorithm doesn't seem to be fully bi-directional. In the example above, we'd like to get from 0066620694, a paperback, to 0875845851, a hardcover. But although we can get from 0875845851 to 0066620694, we can't get from 0066620694 to 0875845851. [Jon's Radio: Multi-ISBN LibraryLookup]
Those two links didn't used to yield the same set of ISBNs. Now they do. Cool! … [Jon's Radio]