An old bookmark can tell you where someone’s interest once stopped.

A bookmark left in place is an unintended record. Something ended there: attention, time, patience, or a life that got busy in another direction, and the page number is the only surviving evidence. Finding one in a second-hand book puts you in company with a stranger who went exactly this far and no further.

If you find an abandoned marker in your own shelves, read a page either side before deciding what to do. You may remember why you stopped, and the reason may no longer apply. Some books are waiting rather than finished with.