The author was impressed by the amount of information about local criminals disseminated among police officers, by the flow of information from criminal sources, and the sometimes spectacular success of the technique of suspicion. In addition, the police deployed considerable resources in investigating major incidents and managed them in a systematic and exhaustive manner to explore all lines of inquiry. The police played only a small role in discovering indictable crimes, since most offenses were reported by the victim or other members of the public. However, the admission of previously unreported offenses during the interview and searches of persons coming into police custody were responsible for the police discovering an important minority of previously unreported crimes. The detection rate for more serious offenses was slightly higher than in the random sample, 46 percent compared to 41.2 percent. A significant minority of suspects was arrested but subsequently released without being charged, particularly in investigations of more serious crimes. This appeared to occur because police felt they had made a mistake rather than they were unable to produce sufficient evidence for a charge. The study confirmed that the circumstances of the offense largely determined what could be done to detect it and that statistics on crime submitted to the Home Office were prepared with care and accuracy. It further concluded that no obvious powers that police could be given would greatly enhance their effectiveness in detecting crime, but that the interviewing of persons arrested played a central role in crime detection. Tables, footnotes, and approximately 50 references are included.