Long before television and radio commercials beckoned to potential buyers, the medicine show provided free entertainment and promised cures for everything from corns to cancer. Combining elements of the circus, theater, vaudeville, and good old-fashioned entrepreneurship, the showmen of the American medicine show sold tonics, ointments, pills, extracts and a host of other "wonder-cures," guaranteed to "cure what ails you." While the cures were seldom miraculous, the medicine show was an important part of American culture and of performance history. Harry Houdini, Buster Keaton, and P.T....