Book excerpt: The Federal Bureau of Investigation (FBI), Central Intelligence Agency (CIA), and National Security Agency (NSA) have been protecting Americans for decades. The events following the 9/11 attacks led to the creation of the Department of Homeland Security in 2002. Inside, you will find a thorough examination of each agency and department-its creation, history, structure, inner workings, and importance as they work hard to protect Americans at home and abroad. Book jacket.