The spy is the most contradictory hero in cinema. Although money and sex have motivated many spies in real life and fiction, the essential motivating force behind espionage is devotion to a cause, usually a nation, that is best expressed by concealing it. Because successful spies place loyalty to their country—or to their faction, their insurgency, or their political agenda—over all other loyalties, including their ties to family and friends, the lives they lead are lies. They may seem to be ordinary citizens, even citizens of enemy nations, but the mission that drives them can succeed only to the extent that it is hidden from those around them.
The most successful real-life spies may well remain unknown to this day. But since popular entertainment has no room for unknown heroes, spy films feature either unsuccessful spies, characters whose covert attempts to gather secret information about their cause's enemies are doomed to failure when they are unmasked, or spies like James Bond, whose success is somehow compatible with conventional Hollywood heroism, even fame among his fictional peers. These two character types represent the two leading tendencies in spy films.