Sichuan renmin chubanshe (四川人民出版社)
From December 1968 onward, millions of urban youth (secondary school graduates and students) were sent "up to the mountains and down to the villages" (shangshan xiaxiang), i.e. to rural villages and to frontier settlements. There, they had to strike root, in order to be reeducated by the Poor and Lower-Middle peasants, the lowest classes in China.
The slogan on the banner in the background reads "Always follow the course of cooperation with workers-soldiers-peasants".