This movie's preamble explains the importance of salesmanship after the great depression The industrial revolution has created a life of modern convenience for America, and there are more products available than most people can fathom. David, one of the main characters in this drama, is a life insurance salesman. His livelihood and profession rely on people willing to take out new policies. Throughout the beginning of the film, a narrator points out modern inventions like telephones, electric toasters, and other conveniences, and explains the significance of these items.