Common methods and themes in crime thrillers are mainly ransoms, captivities, heists, revenge, kidnappings. More common in mystery thrillers are investigations and the whodunit technique. Common elements in psychological thrillers are mind games, psychological themes, stalking, confinement/deathtraps, horror-of-personality, and obsession. Elements such as fringe theories, false accusations and paranoia are common in paranoid thrillers. Threats to entire countries, spies, espionage, conspiracies, assassins and electronic surveillance are common in spy thrillers[11] The primary elements of the thriller genre: The protagonist(s) faces death, either their own or somebody else's. The force(s) of antagonism must initially be cleverer and/or stronger than the protagonist's. The main storyline for the protagonist is either a quest or a character who cannot be put down. The main plotline focuses on a mystery that must be solved. The film's narrative construction is dominated by the protagonist's point of view. All action and characters must be credibly realistic/natural in their representation on screen. The two major themes that underpin the thriller genre are the desire for justice and the morality of individuals. One small, but significant, aspect of a thriller is the presence of innocence in what is seen as an essentially corrupt world. The protagonist(s) and antagonist(s) may battle, themselves and each other, not just on a physical level, but on a mental one as well. Either by accident or their own curiousness, characters are dragged into a dangerous conflict or situation that they are not prepared to resolve. Characters include criminals, stalkers, assassins, innocent victims (often on the run), menaced women, characters with deep dark pasts, psychotic individuals, spree killers, sociopaths, agents, terrorists, cops and escaped cons, private eyes, people involved in twisted relationships, world-weary men and women, psycho-fiends, and more. The themes frequently include terrorism, political conspiracy, pursuit, or romantic triangles leading to murder.[12] The protagonists are frequently ordinary citizens unaccustomed to danger, although commonly in crime thrillers, they may also be "hard men" accustomed to danger such as police officers and detectives. While protagonists of thrillers have traditionally been men, women lead characters are increasingly common.[13] In psychological thrillers, the protagonists are reliant on their mental resources, whether it be by battling wits with the antagonist or by battling for equilibrium in the character's own mind. The suspense often comes from two or more characters preying upon one another's minds, either by playing deceptive games with the other or by merely trying to demolish the other's mental state. http://en.wikipedia.org/wiki/Thriller_%28genre%29