Stand alone Teen/YA novels?

Dangerous Days and Blades, both by J. William Turner. Very realistic fiction about Australian teens in several tense, dramatic, life and death situations set in many parts of Australia, plus England and California, and deals with teenage, adult and social themes. More info in Yahoo web search. Although these two novels are not an official series, the main teen characters in Dangerous Days do re-appear in Blades as adults.