Based on a review of the embryology, genetics, and anatomy of radial club hand, it is suggested that damage to the apical ectoderm on the anterior aspect of a developing limb bud leads to the deformity. Study of the families of thirty-five children with radial club hand suggested that the condition is not genetically patterned. The anatomical findings and associated congenital abnormalities in the cases known to be related to thalidomide and in those in which thalidomide was not a factor were similar except that the incidence of other skeletal deficiencies was higher in the thalidomide group. Thirty-one of the 117 radial club-hand deformities (in sixty-eight patients) under my personal supervision were treated by centralization of the carpus on the ulna with satisfactory improvement of the deformity. In three cases wrist deformity recurred mainly in a volar direction, apparently the result of muscle imbalance. No significant impairment of ulnar growth occurred and straightening of the wrist did not affect function adversely. Pollicization of the index finger was done on twenty-eight occasions. Although problems developed in the early cases, these can be avoided using the methods described and the operation can improve both function and appearance. A scheme of management is recommended.