In 1976, Zhang enlisted in the armed forces and became a clerk in his hometown in Shangqiu, Henan province. After retirement in 1984, he taught at a school in the city.

Zhang first came to Xinjiang after having conflicts with his family in 1994. With little money, Zhang became a ragman. While scavenging old or unwanted items to sell, he found lots of books piled up in recycling stations.

Sometimes, he would lie on the pile and read books like Journey to the West after he finished work.

Then, in 1998, he decided to make a living by buying and reselling used books.

He bought books from recycling stations at a price triple that of waste paper and sold those that he did not want in the market at a good price.

"Years later, about half of the locals knew me and would sell their used books to me. I also bought books which had become obsolete in libraries and government departments," he said.

He would pay much higher prices for some books that he valued a lot. For example, he negotiated four times with staff from the recycling station for the Selected Works of Mao Zedong, and eventually bought it at 200 yuan ($29.60), though its original price was about 20 yuan.

In 2013, Zhang turned four out of nine rooms in his house into a library and opened it free of charge. He manages the library with his wife. In addition, he has set up seven book corners across the city.

"Before, it was hard for me to borrow a book, and now I like to share mine with others. They can read books here in the library or take them home," he said.

"However, with the internet and mobile phones, fewer people now come to my library than before," he added.

For 20 years, Zhang has spent nearly all his money purchasing books, and he even owes his friends about 20,000 yuan after preparing for his son's wedding.

However, he said he is a "rich" man and feels satisfied with his life. "It was books that gave me the courage to get through difficulties and carry on living. Now, I am a member of the Aksu poetry academy. And I got to know lots of friends through sharing books," said Zhang.

"Though my family is still far from being an intellectual one, I believe it will be in the future, because my descendants will inherit my spirit and wealth of books."