Doesn’t the library of Congress in the US issue ISBN numbers for each book published. there must be a public listing of those.
After some looking, there are Some private databases with millions of # but no official site. Eg
After some looking, there are Some private databases with millions of # but no official site. Eg
For books in the collections of large libraries (like the LoC) there will be a public catalogue entry with the ISBN attached, but they don't assign it.
There were also a lot of books published before ISBNs were created, and not every book has an ISBN attached even to this day.
https://en.wikipedia.org/wiki/International_Standard_Book_Nu...