BobC wrote:
I've used Books a bit (although not in a while), and found a way to speed things up (subjectively) somewhat for large batches.

If you scan or type(*) your ISBNs into a text document, you can zip through as many as you want to put in a batch. Then you can tell Books to import the list of numbers and do its lookups for the batch while you do something else. It won't take less time overall, but there's less time that you're tied up waiting for it, so it'll seem quicker.

(* Judging from your friend's shelves, she may have a lot of esoteric or older books that aren't barcoded, so there may be more manual input needed on the front side.)