"Stage fright is one of the human psyche's deepest fears. Laurence Olivier learned to adapt to it, as have actors Salma Hayek and Hugh Grant. Musicians such as George Harrison and Adele have battled it and learned to cope. Others never do: In 1973, Pittsburgh Pirates All-Star pitcher Steve Blass suddenly could no longer find the strike zone; his career ended soon after. Surveys in the United States repeatedly rank public speaking as one of the top...