If I remember correctly, it wasn't a distinction between common and rare books. It was a distinction between library books and others. They partnered with libr

If I remember correctly, it wasn't a distinction between common and rare books. It was a distinction between library books and others. They partnered with libraries, and obviously, libraries didn't want their books destroyed, so they devised a non-destructive book scanner. Some of the books they scanned were indeed rare, but rare or not, you don't destroy books you borrowed from a library!