A lot. My interest in military history has steered me to the topics I want to explore. I also think a part of me (or someone I know well) is in all my main characters: Gil Martin has my controlled analytical mind; Paul Keller my spirit of adventure and love of baseball; Shannon Tunney my mother’s intelligence, beauty, and fortitude. I assure you, there are a lot of differences too. The chess cypher in So Beware comes from my knowledge of the game.