Espionage

From the Galactic Civilizations Wiki

Espionage represents efforts to gather intelligence about a specific race. Espionage builds up over time, and can eventually lead to theft of technology. The more credits spent on espionage, the faster the buildup effect. The espionage level can be set on the "Relations" tab on the Foreign Policy screen.

Low	Income/influence ratings on planets Ship destinations General civilization statistics such as total population, average approval, etc.
Medium	Race bonuses (with all mining, anomaly, and technology bonuses) Medium planet info(?) Low level technology list + current research project
High	Planetary improvements Mid level technology list
Advanced	Starbase information Full technology list Occasional stolen technology

Note that although "Destabilization" is mentioned in the manual it was removed from the final build of the game, although it exists in Dark Avatar.

[edit] Stopping Espionage

Currently (patch 1.11) there is no way to stop the other civilizations from stealing your technology. You also do not know about it until after the game ends.