Dr Samuel Johnson was noted by his friends to have almost constant tics and gesticulations, which startled those who met him for the first time. He also made noises and whistling sounds; he made repeated sounds and words and irregular or blowing respiratory noises. Further, he often carried out pronounced compulsive acts, such as touching posts, measuring his footsteps on leaving a room, and performing peculiar complex gestures and steps before crossing a threshold. His symptoms of (a) involuntary muscle jerking movements and complex motor acts, (b) involuntary vocalisation, and (c) compulsive actions constitute the symptom complex of Gilles de la Tourette syndrome (Tourette's syndrome), from which Johnson suffered most of his life. This syndrome is of increasing interest recently because it responds to haloperidol, and because there are new insights into a possible biochemical basis for the tics, vocalisations, and compulsions.