Know your enemy--that's the best military strategy. The more a country knows about its enemies, the safer it is, and that's where spies come in to help gather knowledge. Some spies are secret agents who work overseas, others stay home supporting the agents in the field.

"True-life cases!"--Cover.

Undercover speak -- Killer lipstick? -- The spy team -- Case #1: Breaking the code -- Case #2: A secret plan -- Case #3: An American traitor -- Key dates in the history of spying -- In the news -- Help wanted: secret agents.