Haha, yes. Not so many of mine any more, after past cullings, all but a few have ISBNs but a good few of those that do don't have a barcode. Don't know when they started, I have a book here from 1965 (costing fifteen shillings (-:) that doesn't seem to have an ISBN at all, it's a charming book about how to drive that mentions things like the new electronic turn signals. Fortunately, books being very old tended to correlate with not worth mentioning in this post anyway.