If human service personnel are to serve clients effectively, they must understand the condition of human need and the objects of need which satisfy the condition. While definitions of need vary according to academic discipline, a review of literature in ten academic areas revealed that need as a human condition is based upon the existence of particular unmet requirements for well being. Need is constantly in a state of interaction with the needful party's values, health, experience, environment, and other characteristics, and is resolved through a sequence of internal stages. Thus, need is a dynamic process rather than a static condition. Five types of needs (physiological, psychological, social, personal, and integrative) have been identified. Their intensity ranges from survival to inconsequential, and their social scope ranges from individual to societal. If applied in practice, these need concepts and definitions provide means for improving the analysis of human service clientele needs and for enhancing the utilization and effects of program resources. While existing literature characterizes need in several ways, it also highlights the necessity for further investigation of the process by which people perceive their own needs or the indicators that reliably characterize need concepts. (MN)