Duncan Ball (born February 1941) is an American-born Australian author who has written the children's series Selby (about a talking dog named Selby who tries to keep his secret away from his owners) and Emily Eyefinger (about a girl who has an eye on her finger). He also writes under the name of John St Claire.
Duncan was born in February 1941 in Boston, Massachusetts, United States, and was one of three children. When he was four, his family moved to Alaska, where he went to primary school. In his teens, Duncan moved to Madrid, Spain where he learned to speak Spanish. He finished high school in the United States, studied at Northeastern University and, later, at the University of Paris (Sorbonne). He has a degree in Mathematics from Boston University.
Ball moved to Sydney in 1974 and worked as an industrial chemist. He wrote a novel for adults and later changed jobs to editor of the School Magazine at the Department of Education of New South Wales. He continued to work there for a few years, then resigned to become a full-time author, a profession which he continues today.