Edit: Alas, some errors regarding "Book not in collection" and "No ISBN". But I think I can probably see if there is a way to contribute those books to the repository.
The importer is a new project (as of August this year) and I think there's a lot of opportunity for improving it (including importing missing records on demand).
Other hat tips: I also want to call out the great work of https://inventaire.io, another great project in the space which uses wikidata, as they also have a goodreads import which we're learning from. Another project I'm excited about (which has goodreads import) is beta.thestorygraph.com. Not sure the status of its source code but I heard an interview from the founder and she and her work so far seems great.
As one can for example add Audible podcasts as books in GR I can imagine this leading to importer errors as well as they necessarily don't need to have an ISBN.
Books pre ~1973 don't have ISBN. And goodreads covers far more material than just modern material.
The current Goodreads importer makes a big/unfortunate tradeoff of trying to have something which works for the majority of material on people's goodreads lists.
It doesn't preclude further efforts -- Open Library knows about millions of books that don't have ISBN. So if anyone wants to help us improve our importer (or at least register their interest by creating an issue which calls out what other identifiers should be considered -- e.g. LOC, etc) that would be very helpful.
Thanks a lot. I learned something today. I knew of the ISBN issue, but didn't think of it.
Having some free time on my hands I will take a look in the next few days. Looking for an alternative to GR and for something that tickles my interests.
I can confirm it works with at least my import.
Edit: Alas, some errors regarding "Book not in collection" and "No ISBN". But I think I can probably see if there is a way to contribute those books to the repository.