The Federal Bureau of Investigation defines its mission in clear terms: to protect and defend the United States against terrorist and foreign intelligence threats, to uphold and enforce the criminal laws of the United States, and to provide leadership and criminal justice services to federal, state, municipal, and international agencies and partners. But the organization now known as the FBI began its history nearly 100 years ago as a small team of 34 Secret Service investigators who were borrowed from the Treasury Department and were not allowed to carry firearms or make an arrest. ""The Federal Bureau of Investigation"" explores the bureau from its beginnings to the present, reviews the tools and techniques used to solve crimes, and explains what a career in the FBI involves.