This document contains a literature review and a discussion of issues concerned with the locus of control dimension in psychological experimentation over the past 15 years. Locus of control research is traced from the early laboratory experiments which demonstrated that instructions and perceptions about skill and chance could dramatically affect subjects' performance, to field research investigating whether individuals carry generalized expectancies about the control of reinforcement. The paper focuses on three specific areas that are emerging in the research and have implications for further understanding of expectancies about locus of control and behavior in general. (1) The first topic is the relationship between belief in internal control and physical health. In general,"internals" have been found to be most likely to take preventive measures to stay healthy. (2) The second area has to do with the relationship between internal control and emotional well-being. Results have been quite similar to the studies dealing with physical health. (3) The final topic concerns perceived power and personal competence. However, little research evidence is available on this topic. (DP)