Spy
A spy is a special kind of undercover agent trained to infiltrate organizations and covertly gather classified information or sow discord. They most typically work for an intelligence community of a government, although corporations and other major institutions also employ spies to infiltrate organizations and covertly gather classified information about their activities.
Missions
The typical espionage mission involves infiltrating enemy territory to steal military secrets, but that's just the tip of the iceberg. Commercial and industrial espionage flourishes in many parts of the galaxy; and traditional spies often perform missions including industrial sabotage, theft of scientific, military or trade secrets, assassination, search and rescue, and counterintelligence operations.
Background
Intelligence agencies and other groups recruit spies from many professions and backgrounds, including rogues, starship officers, soldiers and diplomats. Even scientists, merchants and metaphysicists occasionally become involved in "the great game" due to their wide-ranging travels and ability to cross borders with relative ease.
Role
While the diplomat speaks of joint enterprise and the trader plies the space lanes in peace, a hidden war is being waged in the shadows. Every major interstellar power and the myriad of lesser players employ spies and other covert agents, although their methods and purposes for engaging in espionage differ.