Born on 14 July 1871 at Deptford, Kent, second son of Edwin Unwin, master printer, and Elizabeth Spicer, his wife. His younger brother Stanley became chairman of George Allen and Unwin Ltd, publishers, was president of the Publishers' Association 1933-35, and was knighted. William Unwin was educated at the City of London School and Charing Cross Hospital, and he won the London University scholarship and gold medal in obstetric medicine at the final MB examination in 1899. After serving as house surgeon at Charing Cross Hospital he took the FRCS in 1901 and the MD in 1903, and then went to New Zealand. He became medical superintendent of Timaru Public Hospital in 1904, and began private practice there in 1907. During the 1914-18 was he was officer-in-charge of the surgical division of No 2 New Zealand General Hospital in England, at Walton-on-Thames. He then went back to New Zealand, where he practised at 59 Church Street, Timaru, in the South Island. He was honorary secretary of the South Canterbury division of the British Medical Association 1922-24, and became president in 1944 of the New Zealand branch, which he had represented at the centenary meeting in London in 1932 and at the annual meeting at Plymouth in 1938. He married in 1904 Phyllis Agnes Florence Hall, and was survived by two sons and a daughter; one son had died before him. Unwin died at 18 Kitchiner Square, Timaru, New Zealand, on Christmas Day 1945, aged 74. His son Peter C S Unwin, MB, ChB New Zealand, succeeded to his practice. Publication: On a series of cases of cancer of the tongue, with S Boyd. *Practitioner*, 1903, 70, 626-653.