How did ancient books spread to the present?

Please don't underestimate the shelf life of paper. Before the invention of CD-ROM, there was a saying that "paper lives for a thousand years". So we can often find many ancient books in ancient tombs.

It goes without saying that earlier bamboo slips, stone carvings are more stable than paper.

Of course, the greater destruction of ancient books actually comes from man-made, destroyed by regime change, or lost by war. These ancient books have been handed down to this day with the help of later generations' manuscripts and books. Of course, due to historical reasons, some ancient books have also appeared abroad. Since ancient Greece, there have been special libraries abroad.