THE POLICE CONCEPTION OF 'CRIME' AND THE DEFINITIONS OF 'NO CRIMES' ARE FIRST DISCUSSED. IT IS NOTED THAT A SIGNIFICANT NUMBER OF INCIDENTS REPORTED TO POLICE ARE EVENTUALLY CLASSIFIED AS 'NO CRIME' IN POLICE RECORDS. AMONG THE TYPES OF CASES CLASSIFIED AS 'NO CRIME' WERE: CYCLE THEFTS; CRIMES WHICH POLICE BELIEVED LACKED A NECESSARY ELEMENT FOR CRIME CLASSIFICATION, SUCH AS CRIMINAL INTENT; INCIDENTS IN WHICH THE VICTIM DOES NOT PRESS CHARGES; INCIDENTS SHOWN NOT TO BE CRIMES DURING SUBSEQUENT INVESTIGATIONS; DOMESTIC INCIDENTS, AND CASES INVOLVING INSUFFICIENT EVIDENCE. FACTORS WHICH MAY AFFECT THE POLICE CLASSIFICATION DECISION (SUCH AS POLICE INTELLIGENCE OR EXPERIENCE) ARE BRIEFLY EXAMINED. FINALLY, THE AUTHORS DISCUSS HOW OPERATIONAL CATEGORIES EMPLOYED BY POLICE CANNOT ALWAYS BE ASSUMED TO HAVE A STANDARD MEANING WHICH WILL CORRESPOND TO THE LAYMEN'S OR CRIMINOLOGIST'S CONCEPTION OF THE CATEGORIES.