The author of this sentence is Liu Xiang, an official, bibliographer and writer of the Western Han Dynasty. The specific source cannot be tested, and some of them are from Liu Xiang's Shuo Yuan.

It means that a good secretary is like medicine. Books can cure people's ignorance if you can make good use of them and study hard.

Liu Xiang and Liu Xin are important figures who re-studied and reorganized hundred schools of thought's works and theories after Confucianism was unified as Confucian classics. He said this not only because of the great role of books, but also because of his experience in the compilation process.

Extended information:

Liu Xiang, whose original name was Gengsheng, was known as Liu Zhonglei, the descendant of Liu Bang's half-brother Liu Jiao and the father of Liu Xin.

His prose is mainly a "narrative record" of Qin Shu's and Kao Kan's ancient books, among which "Jian Ying Chang Ling Shu" and "Narrative Record of Warring States Policy" are well-known, and their main features are simple narrative, fluent theory and ease.

I was ordered to lead the school secretary, and I wrote Bielu, which is the earliest public catalogue of books in China. Today, there are books such as New Preface, Shuoyuan, Biography of Lienv, Warring States Policy and Biography of Liexian, and his book "Five Classics and Tongyi" has a compilation of Ma Guohan, a Qing dynasty. The Songs of Chu was compiled by Liu Xiang, while Shan Hai Jing was compiled by Liu Xiang and his son Liu Xin * * *.

Reference: Baidu Encyclopedia-Books are still medicine.