DECLASSIFIED takes you deeper into the secrets and stories that have shaped our world.

Declassified

Motivations leading people to spy against their own nations tend to fall into one of four categories, as notorious cases demonstrate.

Spycraft

Encryption is a key tool for keeping valuable information secret, but some ingenious minds have managed to crack impenetrable codes.

Special operations require skillful people, but some of the most famous missions in modern history relied on elite technology.

Intelligence officers acquire the information collected by sources, from old-school "dead drops" to high-tech digital transfers.

Methods for capturing sensitive data have grown more advanced as devices have become exponentially smaller.

As long as there has been espionage, sex and the promise of it have been powerful tools of persuasion and blackmail.

For some covert missions, assassination is the goal, and lethal toxins are deployed by spy agencies to kill perceived foes.

In the spy game, listening, learning and gaining the ability to eavesdrop requires ingenuity.

Throughout history, the tools and technologies developed for the spy game matter as much as the spies themselves.