Cerebral palsy (CP) should not be considered as a diagnosis but as a label; it is an umbrella term, primarily affecting posture and mobility. The definition is not sufficiently precise to guarantee agreement as to which patients to include under this label, but the additional inclusion criteria required are not yet internationally standardised. Hippocrates (fifth to fourth century B.C.) was the first to discuss the association of prematurity, congenital infection, and prenatal stress in relation to the pathogenesis of brain damage. William John Little (1810–1894), the founder of orthopaedic surgery in England, was the first personality to intensely engage cerebral palsy. In recent years, scientists have reached a broad consensus on the definition of cerebral palsy. For the fourth edition, the chapter has been reviewed/revised by the Book Editor.