Such things as the eyewitness's identification of perpetrators from lineups, the relationship between the eyewitness's expressed confidence in identifying someone and the accuracy of that identification, and the influence of misleading postevent information on eyewitness memory and reports are examined. The controversy over the application of eyewitness research in the courtroom, is discussed. This debate on expert testimony has sharpened researchers' conceptions of generalization problems and the quality of jurors' knowledge about eyewitness accuracy, as well as raising concerns about the proper role of experimental psychologists in the legal system. The authors maintain that the confusion and controversy over expert testimony stems largely from the fact that it represents an attempt to provide services to the judicial phase, rather than the evidence-production phase, of the fact-finding process. 89 references. (Author abstract modified).