The series Graded Readers for Chinese Language Learners is composed of 50 books, divided into three subseries, namely folktales, literary stories and historical stories, corresponding to Levels 1-3 respectively. 
 
Wu Song tells the story of Wu Song being driven to join the Liangshan rebels. Wu Song was born with extraordinary strength. He killed a tiger with bear hands and became a military officer in Yanggu County. However, his brother was murdered and the local government wouldn’t do him justice. To avenge his brother, Wu Song killed the murderers Pan Jinlian and Ximen Qing and therefore was tattooed on the face and banished to Mengzhou. Later in Mengzhou, Wu Song, being drunk, beat Jiang Menshen out of justice. Then he was framed by Inspector Zhang, but he escaped and killed his enemy. He went to Erlong Mountain and later joined the Liangshan rebels.