Technical Abstract: Riparian zones are generally defined as the area of transition between uplands and aquatic ecosystems associated with streams or lakes. In recent years, a great deal of attention has been placed on riparian ecosystems in the western U.S. The emphasis on both public and private land, has been a result of concerns over water quality, wildlife and fish habitat, and endangered species associated with riparian zones. Agriculture in general, and livestock producers in particular, will be impacted by policy and management decisions associated with riparian zones. Unfortunately, many land managers are unaware of how riparian zones function. This article summarizes existing research on the structure and function of riparian zones and associated streams. The dynamic nature of riparian zones is stressed. If managers do not understand the basic functioning of riparian systems, they will find it difficult to separate changes that result from management and those that are natural.