The selection of children in England's schools for different types of education can be seen operating at three levels: between schools, within schools and within classes. This article deals mainly with the second--the allocation of pupils to classes--but it also refers to selection for secondary education and to the grouping of pupils within classes because decisions at all three levels are interlinked. It describes the ways in which pupils have been allocated to teaching groups since the 1860s, noting relevant sections of government reports and white papers, the arguments made by educationists, and the findings of research projects.