Spensley writes that her book is not primarily a biography but about the distinguished contribution Tustin made to the psychoanalytic investigation of autism. The book has two objectives: to give an account of Tustin's clinical work and principal ideas, and to place her contribution within the tradition of psychoanalytic thinking and theory. She says that much of the book concerns ‘how far Tustin's conceptions of autism match the theoretical models of her analyst (Bion)’. Spensley's knowledge of Tustin and her work is based on the experience of her as supervisor, colleague and friend.