THE TEXTBOOK EXAMINES THE SIGNIFICANCE, GOALS, AND VOLUME OF RESEARCH ON THE PERSONALITY OF A DEFENDANT UNDERGOING INVESTIGATION AND INTERROGATION FOR A CRIME AND THE IMPORTANCE, AS EVIDENCE, OF INFORMATION REGARDNG THE DEFENDANT'S PERSONALITY AND BEHAVIOR. RECOMMENDATIONS ARE MADE FOR ORGANIZING RESEARCH ON THE DEFENDANT'S PERSONALITY ON THE BASIS OF A GENERALIZATION OF LEGAL PRACTICE, AND THE SPECIFIC METHODS OF SUCH RESEARCH ARE PRESENTED. THE ISSUE OF CONSIDERING INFORMATION ON THE DEFENDANT'S PERSONALITY IN THE INDICTMENT IS DISCUSSED. (AUTHOR ABSTRACT MODIFIED -- VA)