THE STUDIES, WHICH MAY BE ORDERED BY ANY DISTRICT COURT JUDGE, ARE PREPARED BY PERSONNEL AT FEDERAL BUREAU OF PRISONS FACILITIES. THE STUDIES ARE INTENDED TO PROVIDE THE JUDGE WITH INFORMATION ON THE CONVICTED OFFENDER'S MENTAL AND PHYSICAL HEALTH, SOCIAL BACKGROUND, AND PREVIOUS CRIMINAL EXPERIENCE, BASED ON DATA GATHERED DURING 90 DAYS OF OBSERVATION AND STUDY (60 DAYS FOR YOUTHFUL OFFENDERS). THE PRESENTENCE STUDY PROCESS IS COMPLEX, INVOLVING A VARIETY OF AGENCIES, PROFESSIONS, AND PROCEDURES. JUDGES, PROBATION OFFICERS, AND CORRECTIONS OFFICIALS HAVE EXPRESSED DISSATISFACTION WITH THE STUDY REPORTS. ON THE BASIS OF UNSTRUCTURED INTERVIEWS WITH PERSONNEL INVOLVED IN PRESENTENCE STUDIES, OBSERVATION OF STUDY PROCEDURES, EVALUATION OF STUDY REPORTS, AND A SURVEY OF REASONS FOR ORDERING STUDIES, CONCLUSIONS ARE DRAWN REGARDING THE ADEQUACY OF THE STUDY PROCESS. A REVISED MODEL FOR BUREAU-PREPARED PRESENTENCE STUDIES IS PRESENTED, AND RECOMMENDATIONS FOR USING STUDIES PERFORMED BY LOCAL PROFESSIONALS AS AN ALTERNATIVE TO BUREAU STUDIES ARE OFFERED. THE NEED FOR JUDICIAL OVERSIGHT OF PRESENTENCE STUDIES AND FOR APPROPRIATE TRAINING FOR JUDGES AND PROBATION OFFICERS IS STRESSED. APPENDIXES INCLUDE METHODOLOGICAL NOTES AND GUIDELINES FOR PREPARING PRESENTENCE STUDY REFERRAL LETTERS. (LKM)