This book introduces the main investigative force in the United States, the Federal Bureau of Investigation (FBI), which is part of the U.S. Department of Justice. Historical information covers Attorney General Charles J. Bonaparte's formation of a federal investigative force, early special agents and the crimes they investigated, original director Stanley W. Finch, famous criminals such as John Dillinger, long-term director J. Edgar Hoover, and investigations during World War II, the Cold War, the Vietnam War, and post-9/11 America. The book highlights the categories of crimes the FBI investigates, including counterintelligence to prevent spying within the United States, counterterrorism to prevent attacks, violent crimes such as kidnapping, organized crime, which might include undercover work, white-collar crime, which relates to illegal business practices, cybercrime to prevent computer attacks, and civil rights such as hate crimes and discrimination. Other chapters introduce the reader to organizational changes after September 11, requirements for application, the FBI Academy, training including weapons, self-defense, law, and science classes, the FBI Laboratory and its studies of fingerprints, DNA, and profiling, the headquarters, and the variety of jobs available from special agents to support such as lawyers, computer experts, and language specialists. Full-color photographs, sidebars, fun facts, a graphic timeline, a glossary, and an index accompany this easy-to-read text.