Liu Fang, an official of the Song Dynasty, was knowledgeable in medicine. His courtesy name was Fangming, and he later changed his name to Liu Dan. His birth year is unknown, and he died in 1150. He became a Jinshi (a successful candidate in the highest imperial examinations) in the sixth year of the Xuanhe era (1124) and later rose to the position of Zhilong Tuge, governing Tanzhou. Moved by the profound suffering of children and the lack of comprehensive pediatric texts to aid them, he compiled the discussions of previous scholars on pediatrics. He tasked his administrative officer Wang Li and the provincial graduate Wang Shi to co-edit the material, resulting in a massive tome titled "Youyou Xinshu," comprising forty volumes. Due to illness, the final two volumes were prefaced by his disciple Li Geng on his behalf. The book extensively references earlier materials, including many medical works and other documents that have since been lost, thus holding significant bibliographic value. It represents the culmination of pediatric science before the Song Dynasty.