THE THREE PRINCIPLE SOURCES OF DATA WHICH THE COURT USED IN FORMULATING THE HYPOTHESIS OF POLICE INTERROGATION UPON WHICH MIRANDA WAS DECIDED ARE IDENTIFIED AND EXAMINED. DATA RELATIVE TO POLICE INTERROGATION PRACTICES AVAILABLE FROM CONGRESSIONAL COMMITTEES AND GOVERNMENTAL COMMISSIONS FOR THE COURT'S CONSIDERATION BUT UNRESEARCHED BEFORE THE RULING ARE ALSO ANALYZED. INFORMATION OBTAINED FROM HEARINGS AND COMMISSION REPORTS SUBSEQUENT TO THE MIRANDA RULING ARE ALSO PRESENTED AS A MEANS OF EVALUATING THE COURT'S ASSESSMENT OF POLICE INTERROGATION PROCEDURES IN MIRANDA. THE AUTHOR CONCLUDES THAT JUDICIAL DECISIONS BASED ON FACTUAL DATA WOULD LEAD TO A MORE RESTRAINED FORM OF JUDICIAL DECISION-MAKING COMPATIBLE WITH THE TENETS OF REPRESENTATIVE DEMOCRACY.