Descriptions of various psychotic symptoms in children began to appear in the psychiatric literature at about the same time as descriptions of psychotic symptoms in adults. For example, Kraepelin estimated that at least 3.5 percent of his cases of dementia praecox had onsets before age 10. The construct of “childhood schizophrenia” initially emerged from attempts to classify a broad range of psychotic children. By the late 1940s and 1950s, the diagnosis of “childhood schizophrenia” was given to many disturbed children who today would be considered to have infantile autism and other developmental disabilities. In the early 1970s infantile autism and its variants was differentiated from schizophrenia of childhood onset. These changes were incorporated in DSM-III, which returned to the practice before 1930 of diagnosing schizophrenia in children using the same criteria as for adults, with minor allowances for differences in the manifestations of these symptoms during childhood. The studies presented in this issue of Schizophrenia Bulletin use DSM-III, DSM-III-R, or ICD-9 criteria for schizophrenia.