Davidson Sylvester Hector Willoughby Nicol had a multifaceted personality and made outstanding contributions in a number of fields such as diplomacy, medical practice, teaching and research, and literature.

Born in Sierra Leone, he studied medicine at Cambridge and London Universities. He later taught medicine in Great Britain and Nigeria and did medical research, most famously in the structure of insulin. He was also a Vice-Chancellor at the University of Sierra Leone.

From 1969 to 1971, he served as Permanent Representative of Sierra Leone to the United Nations. He was head of the UN Committee on decolonization and president of the UN Security Council during the 1970 hostages’ crisis. Following these appointments, he also represented his country as High Commissioner in London, and as Ambassador in Norway, Sweden and Denmark. In 1972, he was appointed Under-Secretary-General of the United Nations and Executive Director of UNITAR and remained at this post until 1982. From 1983 to 1987, he held the position of president of the World Federation of the UN Associations.

Davidson Nicol published extensively on Africa and the United Nations. He also wrote short stories and poems under the name Abioseh Nicol.