Bob Lee Swagger Series by Stephen Hunter
Violent, fast thrillers with almost mythic
Start with: Point of Impact (Beth R.)

Sam Capra Series by Jeff Abbott
Action-packed, fast-paced and suspenseful, with great characterizations but driven by its plot.
Start with: Adrenaline (Jackie S.)

John Rain Series by Barry Eisler
Full-speed-ahead series taking place outside of the U.S. and featuring a former black-ops spy who is a “moral” killer and an outsider.
Start with: Rain Fall (Beth R.)

SIGMA Series by James Rollins

Protagonist is a man who can handle a gun, but also has a brain. Series has plenty of
military overtones and a ton of action.
Start with: Map of Bones (Danielle K.)