THE DATA CONCERN THE AGE AND SEX OF OFFENDERS, THE KINDS OF OFFENSES COMMITTED, AND PREVIOUS CONVICTIONS. EVERY THIRD PERSON CONVICTED OF A CRIMINAL OFFENSE WAS 10 TO 20 YEARS OLD (A JUVENILE). THE AGE MEDIAN OF CONVICTED PERSONS FELL FROM 29 TO 25, BUT THIS DROP WAS ONLY PARTIALLY DUE TO DEMOGRAPHIC CHANGES, SINCE THE SAME TREND APPEARED ALSO WHEN THE AGE STRUCTURE OF THE POPULATION AND THE TOTAL INCREASE IN CONVICTIONS WERE HELD CONSTANT. MEN FORMED THE MAIN BODY OF CONVICTED PERSONS, WHILE THE RATIO OF WOMEN TO ALL OFFENDERS SHOWED A STEADY FALL. IN 1955, FOR EVERY 100 CONVICTED MALES 30 FEMALES WERE CONVICTED, AS COMPARED WITH 20 IN 1965, AND 14 IN 1975. A SIMILAR TREND WAS TRUE FOR JUVENILE OFFENDERS: IN 1959 TO 1969 THERE WERE 12 GIRLS FOR 100 BOYS CONVICTED, AND BY 1975 THE NUMBER OF GIRLS FELL TO 8. DATA CONCERNING THE KINDS OF CRIMES (STRUCTURE OF CRIMINALITY) SHOWED REMARKABLE STABILITY. OUT OF EVERY 20 ADULTS, 8 WERE CONVICTED FOR OFFENSES AGAINST PROPERTY, 3 TO 4 FOR ROAD OFFENSES, 2 FOR CRIMES AGAINST OFFICIALS, 1 FOR PROPERTY CRIMES, AND 3 TO 4 FOR OTHER OFFENSES. WHEN FLUCTUATIONS DID OCCUR, THEY WERE THE RESULT OF LEGISLATIVE CHANGES, CHANGES IN LAW ENFORCEMENT METHODS, AND CHANGES IN RECORDKEEPING, AS WELL AS OF THE REAL OFFENSE FREQUENCY. FOR EXAMPLE, THE RATIO OF ROAD OFFENSES TO OTHER OFFENSES ROSE FROM 0.5 PERCENT IN 1957 TO 5.3 PERCENT IN 1972 AS A RESULT OF THE GREATER NUMBER OF CARS ON THE ROADS, BUT THIS TREND LEVELLED OFF IN THE YEARS AFTER 1972, FOLLOWING THE APPLICATION OF DRUNK DRIVING LEGISLATION, WHICH WAS USED FOR TWO-THIRDS OF THE ROAD CONVICTIONS. THE RATIO OF PREVIOUSLY CONVICTED PERSONS TO THE TOTAL NUMBER OF CONVICTED ADULTS SHOWED GRADUAL INCREASE (TO 35 PERCENT IN 1975), BUT THIS WAS PARTIALLY DUE TO IMPROVEMENTS IN RECORDKEEPING TECHNIQUES. TABULAR DATA, FOOTNOTES, AND AN APPENDIX ON THE LEGISLATIVE REFORMS ARE INCLUDED. -- IN POLISH.