Modern comprehensive multidisciplinary mental-health services for children and adolescents have four origins: psychology from 1890, psychoanalysis from 1906, the child-guidance movement from 1920, and the children's departments of psychiatric teaching hospitals from 1930. Post-war changes in society and reform, especially the NHS Act 1946, contributed to rapid development of services and an increasingly wide range of sophisticated therapeutic interventions; professional and interdisciplinary associations and trans-Atlantic exchange were also influential. In the last three decades a succession of official inquiries, reports, legislation and reorganisations have had a damaging effect. Children and their services have been prey to causes célèbres, fashion and the exaggerated fads and foibles of the media and politicians; they have thrived best when society and their carers were tolerant, and loving, sought good qualities to augment, not evil to exorcise, and succeeded in balancing structure and control with flexibility and freedom to grow. Planners should review the past before acting.