To listen to the media, humans are scarred of many things, from terrorists, wars, and catastrophes to strange diseases like bird flu and SARS. But concern about these real dangers is not what makes people literally sick of fear. Neither is it anxieties about unemployment or lack of savings, justified as they may be these days. Far more frequently, those whose apprehensiveness brings them to seek psychiatric care suffer from unrealistic fears: sidewalks, elevators, trains, criticism, undetected disease. All fear has a purpose, though. The rational kind protects our safety, as when fear of automobile accidents motivates us to wear seat-belts. Likewise, the irrational kind also plays an important role in our lives. The Danish philosopher Søren Kierkegaard wrote that fear “not only paralyzes; it also contains the unending possibility of our ability that serves as the motor of human development.” Though it may sound paradoxical, the great human achievements in art, music, literature, and science all stem indirectly from fear.