Denis Dunn was born in Newcastle-upon-Tyne on 25 February 1916. His father Herbert Gibson Dunn was a sales representative in drapery: his mother was Frances Ethelwyn née Hawdon. From the Royal Grammar School, Newcastle-upon-Tyne, he entered Durham University and completed his clinical studies at the medical school of Newcastle-upon-Tyne, where he qualified in 1938. As a pacifist he did not serve in the Armed Forces, but took a number of junior surgical appointments, eventually training in orthopaedics under Joseph Trueta and Sir Max Page at Oxford, and Sir Reginald Watson-Jones and Sir Henry Osmond-Clarke at the London Hospital. He was appointed consultant orthopaedic surgeon at the Colchester and District Hospital Group, but retained an appointment as an honorary assistant surgeon in the accident and orthopaedic department at the London, where students found him a most helpful teacher. His interests included silversmithing and playing the bagpipes, both Northumbrian and Scottish. In 1941 he married a Miss Hodgkiss. They had one son (a doctor) and one daughter. He died on 8 March 2001.