DETAILED CASE RECORDS MAINTAINED BY THE NATIONAL PAROLE BOARD OF CANADA ON EACH CONVICTED DANGEROUS SEXUAL OFFENDER SERVED AS THE PRIMARY SOURCE OF DATA FOR THIS STUDY. EACH CASE RECORD WAS EXAMINED TO OBTAIN INFORMATION ON THE SUBJECT'S PERSONAL CHARACTERISTICS, HIS CRIMINAL HISTORY, THE NATURE OF HIS MOST CURRENT OFFENSES, THE AGE AND SEX OF HIS VICTIM(S), AND THE DETAILS OF HIS TRIAL PROCESS, INSTITUTIONAL EXPERIENCE, TREATMENT HISTORY, AND PAROLE. BETWEEN 1949, THE YEAR IN WHICH THE FIRST LEGISLATION ON DANGEROUS SEX OFFENDERS (DSO) WAS ENACTED, AND 1973, 98 OFFENDERS WERE CONVICTED AS DSO'S IN CANADA. ABOUT 62 PERCENT OF THE CONVICTIONS LEADING TO A DSO FINDING WERE FOR HETEROSEXUAL OFFENSES. AMONG THESE, INDECENT ASSAULT, RAPE, AND ATTEMPTED RAPE WERE THE MOST FREQUENT OFFENSES. INDECENT ASSAULT AND GROSS INDECENCY WERE THE MOST FREQUENT HOMOSEXUAL OFFENSES, ACCOUNTING FOR 47 PERCENT AND 37 PERCENT OF THESE OFFENSES RESPECTIVELY. HETEROSEXUAL OFFENDERS AS A GROUP WERE CONSISTENTLY YOUNGER THAN HOMOSEXUAL OFFENDERS, AND THE DSO'S CONVICTED OF RAPE OR ATTEMPTED RAPE TENDED TO BE YOUNGER THAN THOSE INVOLVED IN OTHER SEXUAL OFFENSES. OF THE DSO'S, 5 PERCENT WERE FIRST OFFENDERS AND 13 PERCENT HAD A HISTORY OF ONLY ONE PREVIOUS PERSONAL OR PROPERTY CONVICTION. ALMOST TWO-THIRDS OF THE VICTIMS OF SEXUAL ASSAULTS BY DSO'S WERE FEMALE; OF THESE, ALMOST ONE-HALF WERE YOUNG GIRLS UNDER THE AGE OF 12, AND AN ADDITIONAL 23 PERCENT WERE BETWEEN 12 AND 15 YEARS OF AGE. OF THE 35 MALE VICTIMS, ONE-FIFTH WERE UNDER 12, WHILE ALMOST TWO-THIRDS WERE BETWEEN 12 AND 15. AS OF 1973, 34 PERCENT OF THE DSO'S HAD BEEN PAROLED, FOLLOWING VARIOUS PERIODS OF INCARCERATION. OVER HALF OF THESE MEN HAD BEEN IMPRISONED FOR 6 TO 10 YEARS, AND AN ADDITIONAL 29 PERCENT HAD SERVED BETWEEN 11 AND 15 BEFORE BEING PAROLED. SLIGHTLY MORE THAN HALF OF THOSE PAROLED MADE SUCCESSFUL ADJUSTMENTS. TABULAR DATA ARE PROVIDED. THE APPENDIXES INCLUDE A HISTORY OF DSO LEGISLATION IN CANADA, CASE HISTORIES OF THE DSO'S WHO WERE FIRST OFFENDERS, AND CASE RECORDS OF THE TWO DSO'S WHO HAVE BEEN INCARCERATED FOR MORE THAN TWENTY YEARS. (RCB)