Robert Cohn is a character from the novel "The Sun Also Rises" by Ernest Hemingway. He is an American expatriate living in Paris after World War I. Cohn is portrayed as a sensitive and introspective writer who struggles with feelings of alienation and insecurity among his peers. Cohn is infatuated with Brett Ashley, a beautiful and independent woman, which complicates his relationships with other characters. His quest for acceptance and love leads him to travel with a group of friends to Pamplona for the famous running of the bulls, where his character's vulnerabilities are further explored.