This text suggest that an understanding of police powers can aid in the avoidance of the misuse of such powers. Further, wrongful use of a power of arrest might result in an action against the arrester, and an advantage gained by the unfair collection of evidence might be lost in a trial if the judge forbids its use. The first part contains a general discussion of police powers which has been arranged along the lines of a typical criminal investigation: surveillance, questioning, arrest, search and seizure, and the disposal of property. Also, a survey of licenses and permits and of the authority of the police to issue them is provided. In the second part, legislation relevant to arrest, search, seizure, the issuance of certain forms of authorization, anti-terrorist activities, and domestic violence is discussed. Some sections of the statutes are presented in full, but for ease of reference, many sections have been summarized to provide an accurate note of the essentials, sufficient for all but the most detailed analysis. These statutes include (among others) the Air Force Act of 1955; the Bail Act of 1976; the Betting, Gaming and Lotteries Act of 1963; the Children and Young Persons Acts of 1933 and 1969; the Firearms Act of 1968; the Immigration Act of 1971; the Misuse of Drugs of 1971; the Road Traffic Acts of 1967, 1972, and 1974; and the Prevention of Terrorism Act of 1974. This information is intended to aid law enforcement officials and others interested in the limitations of police power. Lists of court cases and statutes which have been cited are provided. An index is included.