Did you get it right?
This small-town library table shows card-catalog slips, hardcover books, a pencil cup, stamped due-date cards, and a reading lamp. Two little details are too modern.

The Answer
The correct answer is: The peel-off library security-strip backing and the plastic page-marker tab are the two mistakes..
Here is why
- The books, due-date cards, lamp, catalog slips, and reading table fit the period.
- Check the paperwork and the book edges carefully.
- The security-strip backing and plastic tab are modern material clues among old paper items.
Why people miss it
Library tables already have cards, slips, bookmarks, and labels, so the wrong items look like ordinary paper clutter at first glance.
What answer did you get before checking?