I've tried quite a few, and by far Libib was the best. Here's the trick: Books prior to 2005 didn't use ISBNs for their barcodes. They just used some random manufacturer barcode. When you scan those old books, no matter what tool you use, chances are they'll either be wrong, or not come up. That's just the way it is unfortunately. I just make sure that I either type in the ISBN (which is sometimes on the inside covers), or manually enter the older books.