It's interesting how words from your second language can infiltrate your core vocabulary in ways you don't anticipate. I just thought to myself that I now have a nice "stapel" of fountain pen friendly A6 notebooks to keep me busy. It just sounds more correct to me for books than "a pile" or "a stack".
Of course, I'd never deprive you of a chance to admire the stapel...
@0xabad1dea doesn't English "staple" have the same meaning (among many others)?