百读不厌. [bǎi dú bú yàn]

• be worth reading a hundred times:

  You never get tired of reading this book.

  这部书百读不厌。

  In his later years, he devoted all his time to a novel which proved to be a best-loved book.

  到了晚年， 他用全部时间写成了这本令人百读不厌的小说。