Meriwether Lewis, commander of the famed Lewis and Clark Expedition that explored the newly purchased Louisiana Territory from 1804-06, returned home from this perilous journey with every hope as well as his country's expectations of a bright and productive future. Yet within three years, the 35-year-old Lewis was dead in a lonely inn along the Natchez Trace in rural Tennessee, the victim of two gunshots. Various medical and psychological theories have been proposed by historians and other...