text: In World War II Eshelby began working for the Admiralty on the degaussing of ships, but on 4 May 1940 he joined the Technical Branch of the Royal Air Force. His work from February 1941 to June 1942 was for the Coastal Command Development Unit conducting performance trials of Air-to-Surface Vessel radar  and other operational devices in all types of aircraft. He was then involved in radar work, from August 1942 to February 1943 with 76 signals wing and from February 1943 to September 1944 at the radar establishment at Malvern. He was then transferred to disarmament work and then to the Air Historical branch in September 1945. He left the RAF as a squadron leader on 4 October 1946.
  After the war Eshelby returned to Bristol University to study for a PhD and taught himself the theory of elasticity for his thesis on "Stationary and moving dislocations". He obtained his PhD in 1950 under Nevill Mott. In 1951 he moved to the University of Illinois Urbana-Champaign as a Research Associate, where he stayed until 1953 when he was appointed a lecturer at the University of Birmingham, where he taught from 1953 to 1964 at the Department of Metallurgy. During this time, he worked on point defects and dislocations, developing the method of transformation strains and studying the Eshelby inclusion problems for the first time, as well as the study of forces on elastic singularities. 
  In 1964 he moved to the Cavendish Laboratory at Cambridge University at the behest of Neville Mott, and was a Fellow of Churchill College from 1965 to 1966. He was then appointed Reader in the Faculty of Materials (Theory of Materials) at the University of Sheffield, where he became Professor in 1971.