Books are the ladder of human progress.

The lights are on at three o'clock and the chicken is on at five o'clock, which is when men are studying. Black-haired people don't know how to study diligently early, and white-haired people regret studying late. ——Yan Zhenqing

Books are friends. Although they are not passionate, they are very loyal. ——Hugo

Ideal books are the key to wisdom. ——Leo Tolstoy