Clifford Stoll had just started work running a huge central computer at a Berkeley lab when he was given the job of figuring out why the carefully kept user accounts were out by 75 cents.
From this tiny beginning began a hunt for a mysterious hacker who was using the Californian computer as an electronic way station to infiltrate dozens of other systems - including the most sensitive military, scientific and intelligence networks in America.
Obsessed with the need to uncover the hacker's identity, Stoll stalked his every move, setting up a sting operation that finally exposed an international spy ring selling secrets to the KGB.
