THE CIRCUIT COURT OF COOK COUNTY, ILL., THE JURISDICTION WHICH ENCOMPASSES CHICAGO, HAS TWO TIERS OF CRIMINAL COURTS KNOWN AS 'BRANCH' AND 'TRIAL' COURTS. BRANCH COURTS HEAR PRELIMINARY MATTERS (SUCH AS BAIL AND PRELIMINARY HEARINGS) IN FELONY CASES AND ALL STAGES BEFORE APPEAL IN MISDEMEANOR CASES. THIS PAPER DESCRIBES THE REPRESENTATION OF FELONY DEFENDANTS BY ONE LAWYER IN BRANCH COURT AND ANOTHER IN TRIAL COURT. DURING A 3-MONTH PERIOD IN 1975 A TOTAL OF 810 FELONIES WERE PROCESSED THROUGH THE TWO COURTS. OF THESE 57.5 PERCENT INVOLVED SEQUENTIAL REPRESENTATION WITH A PRIVATE ATTORNEY INVOLVED SOMEWHERE IN THE SEQUENCE FOR ABOUT HALF THE CASES. UNITARY REPRESENTATION WAS FOUND IN 27.5 PERCENT OF THE CASES WHILE MOST OF THE REST OF THE FILES CONTAINED INCOMPLETE INFORMATION. THE COOK COUNTY PUBLIC DEFENDER'S OFFICE IS ORGANIZED IN SUCH A WAY THAT A DEFENDANT WILL HAVE SIX ATTORNEYS BY THE TIME THE CASE REACHES APPEAL; DIFFERENT LAWYERS HANDLE (1) THE JAIL INTERVIEW, (2) BRANCH COURT, (3) ARRAIGNMENT COURT AFTER INDICTMENT, (4) TRIAL COURT, (5) POSTCONVICTION MOTIONS, AND (6) APPELLATE COURT. FILES BELONG TO THE OFFICE AND THE CASE IS PASSED ROUTINELY FROM ATTORNEY TO ATTORNEY. THE PROCEDURE DOES NOT RUN SMOOTHLY, HOWEVER, WHEN THE CASE GOES FROM A PRIVATE ATTORNEY TO THE PUBLIC DEFENDER, FROM THE DEFENDER TO A PRIVATE ATTORNEY, OR FROM ONE PRIVATE ATTORNEY TO ANOTHER. THE PROBLEMS WHICH ARISE ARE REVIEWED. IT IS RECOMMENDED THAT FURTHER RESEARCH BE DONE TO PINPOINT EXACTLY WHAT EFFECT SEQUENTIAL REPRESENTATION HAS ON THE DEFENDANT'S CASE. OTHERS HAVE SUGGESTED THAT SUCH REPRESENTATION IS UNCOMMON. THIS STUDY POINTS OUT THAT IT IS ALMOST THE NORM IN COOK COUNTY. THE ARTICLE IS HEAVILY FOOTNOTED. (GLR)