Ernest Jones (1879-1958) was arguably the best-known follower of Sigmund Freud. Born in south Wales, he studied at Cardiff and London, qualifying as a psychiatrist. He knew Freud personally, having learned the German language in order to be able to understand his ideas more clearly, and was largely responsible for introducing them to the profession in both Britain and America. In 1913, he founded the British Psycho-Analytical Society.

Jones's writings on the subject of psychoanalysis prompted him to launch The International Journal of Psychoanalysis in 1920. He was also interested in politics, becoming an early member of Plaid Cymru. His first wife was the composer Morfydd Llwyn Owen. His last great work was the authoritative biography of Freud, which he published between 1953 and 1957.