MAJOR INNOVATIONS OF THE NEW SENTENCING SYSTEM, WHICH BECAME EFFECTIVE FEBRUARY 1, 1978, INCLUDE THE REQUIREMENT OF DETERMINATE SENTENCES IN FELONY CASES AND THE REQUIREMENT THAT SENTENCING JUDGES GIVE REASONS FOR THE SELECTION OF PARTICULAR SENTENCES. THE NEW LAW CREATED A CLASS OF OFFENSE FOR WHICH PRISON SENTENCES ARE MANDATORY, AND, IN SOME CASES, MADE LIFE SENTENCES POSSIBLE. PAROLE AS A VEHICLE FOR EARLY RELEASE HAS BEEN ELIMINATED AND SUPERVISED RELEASE FOR THOSE COMPLETING SENTENCES ESTABLISHED. THE NEW LAW REQUIRES THE APPOINTMENT OF A CRIMINAL SENTENCING COMMISSION TO MONITOR THE FISCAL IMPACT PRISON POPULATIONS CAUSED BY THE USE OF DETERMINATE SENTENCES, TO REVIEW THE CRIMINAL CODE, AND TO DEVELOP STANDARDIZED SENTENCING GUIDELINES. THE NEW LAW DOES NOT APPEAR TO HAVE SIGNIFICANTLY AFFECTED THE PROPORTION OF FELONY CASES LIKELY TO BE TRIED OR THE NUMBERS OF PLEAS IN COOK COUNTY. THE MIX OF OFFENSES PROSECUTED DOES NOT APPEAR TO BE AFFECTED, AND CHARGE ATTRITION IN THE PRELIMINARY HEARING HAS COURT HAS NOT INCREASED. THE PERCENTAGE OF CASES BEING PLEASED OUT OR BEING TRIED TO REDUCED CHARGES IN THE PRELIMINARY HEARING COURTS HAS DECREASED, WHEREAS THE PERCENTAGE OF ORIGINAL CHARGES REACHING THE FELONY TRIAL COURTS HAS INCREASED. FURTHER RESEARCH IS NECESSARY. FOOTNOTES AND TABLES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED--LWM)