"There can be no doubt that as a matter of fact a religious life, exclusively pursued, does tend to make the person exceptional and eccentric. I speak not now of your ordinary religious believer, who follows the conventional observances of his country, whether it be Buddhist, Christian, or Mohammedan. His religion has been made for him by others, communicated to him by tradition, determined to fixed forms by imitation, and retained by habit. It would profit us little to study this second-hand religious life. We must make search rather for the original experiences which were the pattern-setters to all this mass of suggested feeling and imitated conduct. These experiences we can only find in individuals for whom religion exists not as a dull habit, but as an acute fever rather. But such individuals are "geniuses" in the religious line; and like many other geniuses who have brought forth fruits effective enough for commemoration in the pages of biography, such religious geniuses have often shown symptoms of nervous instability. Even more perhaps than other kinds of genius, religious leaders have been subject to abnormal psychical visitations. Invariably they have been creatures of exalted emotional sensibility. Often they have led a discordant inner life, and had melancholy during a part of their career. They have known no measure, been liable to obsessions and fixed ideas; and frequently they have fallen into trances, heard voices, seen visions, and presented all sorts of peculiarities which are ordinarily classed as pathological. Often, moreover, these pathological features in their career have helped to give them their religious authority and influence."-- from publisher.