Travel, if viewed as a commodity, is among the world's leading commercial products accounting for $600 billion in economic trade. If viewed as an employment field, commercial travel, tourism, hospitality, and food and beverage service produce 6 million jobs in the United States alone. Tourism is the first, second, or third industry in 41 U.S. states and in 130 other nations. Yet, when most people think of travel, they envision leisure. Few think of the highly specialized knowledge and finely cultivated technical skills needed for a successful career in the industry.