Tourism, typically defined in simple terms as short-term travel for leisure, is actually quite hard to define clearly when one takes a critical perspective on what constitutes tourism or tourists. An example of this difficulty that is frequently offered by those who study the phenomenon of modern tourism (e.g.  or ) is a person who travels to attend a professional conference; although this person is not traveling primarily as a hobby or for leisure, he or she might partake in tourist activities while away from home. Valene Smith, a pioneer in the academic study of tourism, proposes a formula based on three key elements to clarify the meaning of tourism: Tourism = Leisure Time + Discretionary Income + Positive Local Sanctions. While these elements explain what tourism is, quite a lot of other elements are important to address in order to understand what it does. Both tourists and locals feel the impact of tourism in many realms, including economics, culture, social structure, politics, natural and built environments, and even self-perception.
- Valene L. Smith. 1989. Hosts and Guests: The Anthropology of Tourism. Philadelphia: University of Pennsylvania Press.
- Charles R. Goeldner and J. R. Brent Ritchie. 2009. Tourism: Principles, Practices, Philosophies. Hoboken, New Jersey: John Wiley and Sons.