Born on St David's Day 1883 in Rhymney, the third and youngest son of David Rocyn Jones, Arthur came of a family of Welsh bone-setters. His Pembrokeshire great-grandfather, Thomas Jones, was a farmer with a reputation for treating animals, whose son (1822-1877) and grandson (1847-1915) were bone-setters in a practice continued by Rocyn-Jones' eldest brother; another brother was Medical Officer of Health of Monmouthshire. From Lewis School, Pengam, Rocyn Jones went to University College of South Wales and Monmouthshire, and from there to University College, London. On qualifying he became house surgeon at Cardiff Royal Infirmary to Sir John Lynn-Thomas (1861-1939), a general surgeon and pioneer of bone surgery, and then in 1913 became house surgeon at the Royal National Orthopaedic Hospital, where he was joined by Harry Platt, and, before a distinguished cosmopolitan audience, assisted Fred Albee in probably the first spinal arthrodesis in this country. He remained during the first world war as acting surgeon. Thereafter he became consultant, not only on the active staff of the Royal National Orthopaedic Hospital, the West End Hospital for Nervous Diseases and Fulham Hospital, but also to hospitals as far distant as the Prince of Wales and Glen Ely Hospitals in South Wales, the North Wales Sanatorium and the West Suffolk General Hospital at Bury St Edmunds. As senior surgeon and Chairman of the Medical Committee at the Royal National Orthopaedic Hospital after the second world war, he took a leading part in establishing there the Institute of Orthopaedics of the British Postgraduate Medical Federation of the University of London at a time beset with difficulties and doubts. An original member of the British Orthopaedic Association, he became its Vice-President (1946 and 1947) and Archivist (1953). He had an outstanding command of English, both spoken and written, and he was fluent in Welsh also. He made many contributions to literature, especially in orthopaedic history, of which he had a wide knowledge. Examples are provided by the remarkable series of biographical articles published in the British section of the *Journal of bone and joint surgery* from 1948 to 1954, by his Presidential Address on 'The Evolution of Orthopaedic Surgery in Great Britain' to the Orthopaedic Section of the Royal Society of Medicine (*Proc Roy Soc Med* 1937, 31, 19-38) and by his Founders' Lecture on 'The British Orthopaedic Association' at its 50th Anniversary Meeting in 1968 (*J Bone Jt Surg* 1969, 51B, 1). In 1968 a number of the *Journal of bone and joint surgery* was dedicated to him in commemoration of his 85th birthday. Outside orthopaedics, Rocyn Jones was a member of the Council and former Vice-President of the Honorable Society of Cymrodorion (founded 1751), a member of the Cambrian Archaeological Society, Past Master of the London Welsh Lodge of Freemasons and a Deacon at King's Cross Welsh Congregational Chapel. An outstandingly modest and kindly man, he was very happily married to a former nursing sister, daughter of the Vicar of Beaufort. He died at his home on Stanmore Hill on 12 February 1972, aged 88, survived by his widow, Margaret, and by a married daughter, Glayne, a former physiotherapist.