

For fictional spies, see Spy fiction.
Spies or secrect agents are individuals who obtain information that is considered secret or confidential without the permission of the holder of the information. The act of spying, or espionage, is inherently clandestine, as it is taken for granted that it is unwelcome and, in many cases, illegal and punishable by law. It is a subset of intelligence gathering - which otherwise may be conducted from public sources and using perfectly legal and ethical means.