Many persons who pass as musicians are neither temperamental nor musical. A great many of those who ply the art of music do not have musical minds in any basic sense. Their art consists in certain skills often built into a purely matter-of-fact organism. I therefore see no reason why such people in the musical world who do not show any artistic temperament have any reason to boast of the fact. The highly temperamental musician is a species of genius in some degree. As such, he has been described by musicians, scientists, and psychiatrists in a very copious body of literature on the subject, especially that dating since the time of Lombroso, who regarded all geniuses as degenerates. The modern psychiatrist has frequently presented a picturesque view of the temperamental person in terms of the rising science and art of psychiatry, which is supposed to explain all deviations from normal behavior in terms of psychopathology. The old saying was that we are all more or less sane; the psychiatrist today says we are all more or less psychopathic. The current literature on mental hygiene is characterized by this point of view. Another point of view has proved fascinating since the coming in of Freud, in that deviations of this sort are accounted for in terms of suppressions, defense reactions, and other manifestations of the libido. Much light is thrown on the problem by the great musician's exaltation of the artistic mind in action, thus revealing essential temperamental traits on the basis of first-hand experience and artistic theory. A temperamental musician is the most merciless portrayer of his own species. Since the temperamental person is always an interesting person, all of these accounts are lively and each revealing from its own point of view, giving us much genuine insight into the nature of the temperamental person in all fields.