Hoover, J. (John) Edgar (1895–1972), a United States public official. As director of the Federal Bureau of Investigation (FBI) and its predecessors from 1924 until his death in 1972, he was the nation's chief law enforcement official for nearly 50 years. During most of his career, he was one of the most powerful public officials in the United States and one of the most highly respected. In his later years and after his death, however, there was much criticism of his character and official performance.

Taking over a small, inefficient agency, Hoover transformed it into a national institution respected for its scientific methods of crime detection. The FBI became widely acclaimed as one of the world's most efficient bodies for apprehending gangsters, spies, and subversives, and Hoover was viewed as a tough, incorruptible defender of American security. By the 1960's, however, he had become a controversial figure. Critics decried what they considered his authoritarian methods and lack of concern for civil liberties. Some charged that his views were so conservative that he saw all political protest as Communist subversion. After his death, evidence was uncovered that he had abused FBI powers by conducting vendettas against individuals and groups and may have used FBI secret files for political blackmail.

Hoover was born in Washington, D.C. After graduation from George Washington University Law School, he joined the Department of Justice in 1917. He became assistant director of the Bureau of Investigation (a predecessor of the FBI) in 1921.

Hoover wrote Persons in Hiding (1938); Masters of Deceit (1958); A Study of Communism (1962).