What does it take to spot a spy? Not the old trench-coat-wearing cloak-and-dagger caricature of a Cold War-era secret agent. But the modern spy - the insider, perhaps - who can take down a business or betray a government with a digital weapon.

We hear a lot about how global corporations and modern governments are vulnerable to intrusion, even from their own employees. But what does a spy look like and how can he - or she - be caught?

In TO CATCH A SPY, James Olson, the former chief of CIA counterintelligence, calls on the US needs to do a better job stopping threats from Chinese, Russian, and Cuban spy services. Olson shared some of his own spy secrets with Stratfor’s Chief Security Officer Fred Burton.