Although the size of the National Security Agency's operations is classified, intelligence experts estimate that 38,000 people work for the agency.
ORIGIN President Harry S. Truman signed a memorandum establishing the NSA in 1952. The new agency brought together all U.S. military and non-military cryptology activity.
MISSION Obtaining intelligence through surveillance of adversaries' communications. Securing sensitive U.S. government and military communications.
HEADQUARTERS Located at Fort Meade, the NSA has its own off-ramp from the Baltimore-Washington Parkway marked "NSA employees only."
LEADERSHIP NSA directors historically have been lieutenant generals or vice admirals. The current director, Lt. Gen. Keith B. Alexander, was appointed in 2005. The NSA director reports to the director of national intelligence.
Opinion: Former Congressman on Wiretapping Former Congressman Bob Barr (R-Ga.), chairman of Patriots to Restore Checks and Balances (PRCB), discusses wiretapping and surveillance issues legislation and the controversy over executive powers.