Daguan County, Zhaotong City, is located in the mountainous area in the northeast of Yunnan Province. In the past, some villages had no access to roads due to the steep mountains. Library staff in Daguan County used to carry books in backpacks deep in the mountains, which were affectionately called "backpack libraries". After the road was opened, the former "backpack libraries" in Daguan County were gradually upgraded to "mobile book trucks", enriching people's reading life.