Psychological research on behavior in the legal process has addressed two major issues. The first relates to the ways in which 'facts' may be established as legal evidence, whether the issue has to do with evaluating the basic procedural model adopted in any jurisdiction or with more detailed questions about, for example, the accuracy or reliability of accepted methods of eye-witness identification. The second major issue concerns ways in which decisions are made in the legal system. The focus of this latter area of research has generally been the decisionmaking of judges and juries. Research on the preceding issues is reviewed in the area of legal procedures, eyewitness testimony and identification evidence, detecting deception, the psychologist as an expert witness, and decisionmaking by judges and juries. Extensive psychological research has been done on law breaking, probably because it is viewed as a major social problem. Research related to law breaking is reviewed in the areas of the importance of law in controlling behavior, why people break the law, and reactions to law-breaking. A discussion of the nature of psychology and psychological research is appended. References (about 130) are provided. For related documents, See NCJ 70740-48.