As headmaster of Summerhill, Neill taught classes in Algebra, Geometry and Metalworking. He often said that he admired those who were skilled craftsmen more than those whose skills were purely intellectual. (Neill held that although attendance was optional, the classes themselves were rigorous.) He also had special "private lessons" with pupils, which included discussions of personal issues and amounted to a form of
psychotherapy. He later abandoned these "PLs", finding that children who did not have PLs were still cured of delinquent behaviour; he therefore concluded that freedom was the cure, not psychotherapy.
During his teaching career he wrote dozens of books, including the "Dominie" (Scottish word for teacher) series, beginning with
A Dominie's Log (1916). His most influential book was
Summerhill: A Radical Approach to Child Rearing (1960) which created a storm in U.S. educational circles. His last work was his autobiography,
Neill, Neill, Orange Peel! (1973) He also wrote humorous books for children, like
The Last Man Alive (1939).
A. S. Neill was married twice; his second wife Ena Wood Neill administered Summerhill school with him for many decades until their daughter, Zoe Readhead, took over the school as headmistress.