ALL OF THE STUDY SUBJECTS WERE SERVING PRISON SENTENCES FOR ARMED ROBBERY, AND ALL HAD SERVED AT LEAST ONE PRIOR PRISON TERM. NEARLY 75 PERCENT HAD SERVED AT LEAST TWO PRIOR TERMS. THE SUBJECTS AVERAGED NEARLY 39 YEARS OF AGE. THEY HAD COMPLETED AN AVERAGE OF 8 YEARS OF SCHOOL, BUT APPROXIMATELY 80 PERCENT HAD AN INTELLIGENCE LEVEL OF NORMAL OR BRIGHT-NORMAL. THESE FELONS HAD COMMITTED THEIR FIRST SERIOUS JUVENILE OFFENSE AT AN AVERAGE AGE OF 14. THEIR FIRST ARREST WAS GENERALLY 1 YEAR LATER. BEFORE THE AGE OF 18, 32 WERE INCARCERATED. BROKEN HOMES, LOWER ECONOMIC STATUS, AND SIBLING CRIMINAL RECORDS WERE NOT CHARACTERISTIC OF MOST OF THE SAMPLE. THE SAMPLE SIZE (49) IS TOO SMALL TO PERMIT GENERALIZATIONS ABOUT ALL OFFENDERS; THE FINDINGS ARE APPLICABLE TO THIS RESTRICTED GROUP ONLY. DATA WERE GATHERED FROM STRUCTURED INTERVIEWS WITH THE OFFENDERS AND FROM THEIR OFFICIAL CRIMINAL RECORDS. THE INTERVIEW INSTRUMENT WAS A HIGHLY STRUCTURED QUESTIONNAIRE CONSISTING OF BOTH OPEN-ENDED AND CLOSED-ENDED QUESTIONS. IT WAS DIVIDED INTO THREE SECTIONS, CORRESPONDING TO THREE CAREER PERIODS -- JUVENILE, YOUNG ADULT, AND ADULT -- WITH APPROXIMATELY 200 QUESTIONS IN EACH PART. THE QUESTIONNAIRE IS REPRODUCED IN AN APPENDIX. THE STUDY FOCUSED ON THE FOLLOWING PRIMARY ISSUES IN ANALYZING OFFENDERS' RECORDS AND IN CONDUCTING THE INTERVIEWS: THE EXTENT AND PATTERNS OF CRIMINALITY; OFFENDERS' INTERACTIONS WITH THE CRIMINAL JUSTICE SYSTEM; ROLE OF DRUGS AND ALCOHOL; TREATMENT BY THE CRIMINAL JUSTICE SYSTEM; CRIMINAL SOPHISTICATION; USE OF VIOLENCE IN THE CRIMES; SOCIOECONOMIC FACTORS; AND THE TYPING OF OFFENDERS. THE INTERVIEW ITEMS AND FINDINGS IN EACH OF THESE AREAS ARE DISCUSSED IN INDIVIDUAL SECTIONS. THE PATTERNS OF CRIMINAL ACTIVITY REVEALED IN THE INTERVIEWS ARE DISCUSSED; THEY HAVE TO DO WITH THE NUMBER AND TYPE OF CRIMES, THEIR RATE, AND CRIME SPECIALIZATION AND SWITCHING IN THE THREE CAREER PERIODS. MEASURES OF CRIME SERIOUSNESS ARE APPLIED TO THE DATA TO IDENTIFY OFFENDER TYPES AMONG THE SUBJECTS, AND A DISTINCTION IS MADE BETWEEN INTENSIVE AND INTERMITTENT OFFENDERS. CASE HISTORIES ILLUSTRATE EACH TYPE. CONTACTS WITH THE CRIMINAL JUSTICE SYSTEM (POLICE, PROSECUTION, CORRECTIONS) AND THEIR EFFECTS ON CRIMINAL CAREER DEVELOPMENT ARE CONSIDERED. CRIMINAL EDUCATION, THE DEVELOPMENT OF SOPHISTICATION IN COMMITTING CRIMES AND AVOIDING ARREST, AND MOTIVATIONS FOR ENGAGING IN CRIMINAL ACTS ARE DISCUSSED. MAJOR FINDINGS AND CONCLUSIONS IN EACH OF THE AREAS CONSIDERED ARE OUTLINED. THE PRIMARY CONCLUSION IS THAT CRIMINAL CAREER DEVELOPMENT IS QUITE COMPLEX AND DIVERSE, AND MANY TRADITIONAL ASSUMPTIONS ABOUT THE DEVELOPMENT OF HABITUAL OFFENDERS NEED TO BE RECONSIDERED AND RESTUDIED. APPENDIXES OUTLINE AND REVIEW PREVIOUS STUDIES OF CRIMINAL CAREERS AND DISCUSS THE USE AND VALIDITY OF SELF-REPORTED CRIME DATA (USED EXTENSIVELY IN THIS STUDY). SUPPORTING DATA ARE PROVIDED THROUGHOUT THE REPORT.