Spy fiction is a great genre of literature, since it brings together so many enduring elements of the human condition. Spy fiction almost always has characters people can identify with, including the great and good and the mean and nasty.
This form of literature focuses on espionage as a key plot device, and that in itself implies mystery. It also implies betrayal, investigation, chase, violence and a struggle to achieve what seem to be impossible goals.
The genre itself emerged in the early twentieth century, inspired by rivalries and intrigues between the major powers, and the establishment of modern intelligence agencies. It was given new impetus by the development of fascism and communism in the lead-up to World War II, continued to develop during the Cold War, and received a fresh impetus from the emergence of rogue states, international criminal organizations, global terrorist networks, maritime piracy and technological sabotage and espionage as potent threats to Western societies.