According to the Adult Reading Round Table, most adventure novels deal with a male character who follows his own moral code. He will often times go beyond the law to do what he sees as the right thing to do, which puts him in admiringly dangerous situations. This character seldom has strong reciprocal relationships with woman.
Main characters are often placed in extreme situations to make the book flow quickly. The actions of the characters will usually pull the reader along; this gives the book an action-driven plot.
An exotic setting gives the story a sense of adventure. In exotic adventures, it is common for good to triumph over evil with some fantastic elements playing a role in the plot. Secondary characters are frequently lacking in substance. The exotic adventure typically has unrealistic characters that deal with issue that are very black and white. Some examples of exotic adventure novel authors include Wilbur Smith, James Clavell and Hammond Innes.
Techno thrillers usually prey off paranoia, recalling fears of the Cold War or terrorism. These books are usually written aimed at a conservative audience. The hero typically appeals to men more than women; female characters usually stand by their men no matter what and are pompous good girls. Though there is violence within these stories, it is not described in detail. The most famous author of techno adventure books is Tom Clancy.
The character is usually a solitary character. He often times says little and does not talk if he doesn't have anything important to say. He is typically self-righteous and uses strategy rather than guns if possible. Secondary characters are often women who have fallen from a once lofty position and find the main character enthralling. These stories commonly deal with black and white issues and may feature historical or fictional characters. A classic story of the west is the novel "Shane," written by Jack Schaefer in 1949.
Medical thrillers deal with things you might see on headline news. The plot commonly has conspiracies by big medicine companies or HMOs. It shows how the system is corrupt and the protagonist will uncover the dirt even though it could mean her life. The ethical questions are always black and white. Many plots will expect the reader to suspend disbelief for long moments, as they can be far-fetched. A well-known author of the genre is Tess Gerritsen.
Many stories deal with international political conspiracies that are unearthed and exposed. Like techno adventures, they usually play upon some kind of paranoia. Sometimes the character is young and optimistic and pitted against the corrupt system. These stories tend to have very little character development, which makes for a plot-driven book. The main characters are usually men; the female characters are typically beautiful and politically aware.