Children’s issues are a lens to glimpse the development of contemporary Western theory and criticism of children’s literature, which has experienced significant development through revolution of their perception of children since the 1930s. In the West, while the idea about “knowable children” offered a basis for the theory and criticism of children’s literature before the 1970s, the discussions and reflections on “unknowable children” and “impossible children’s literature” from the 1970s onwards brought about great innovations in concept and methodology. From “knowable children” to “elusive childhood”, “children” not only provide important theoretical and methodological resources for the research on Western children’s literature and culture, but also represent a crucial and profound spirit of criticism.