Wow! Any computer types out there who can tell us how this happens?
There is a “booklist” (Books In Print). There may be more these days.
There was a time when Amazon’s “catalog” was merely the Books In Print catalog. If they didn’t have it, and it was in print, they’d custom order it for you just as your local brick and mortar was willing to do.
Someone responsible for data entry or classification made the call to do this (with or without the proper authority to do so).