Helmholtz's career is outlined, and his views on the relationship between science and art are summarized. He was fascinated by illusions, and his account of their use in both science and art is described. Helmholtz's empiricism is discussed, along with its application to hearing. He was responsible for developing an extremely influential "neural place" theory for the perception of tones, and the effects of this theory upon subsequent concepts are traced. Some limitations of recent place theories are outlined, and suggestions are made concerning the contributions of both neural place and neural periodicity information to the perception of acoustic repetition.