Giff Speer is a Military Policeman.
With far more in common with a private investigator series, especially a hard-boiled detective, than a secret agent, the Speer adventures nevertheless fit in because he gets assigned around the world and must go undercover often to solve the case.
The initial books in the series has Speer first a sergeant in the MP.s and then a special, undercover agent. As the series progresses, he eventually retires but, like all good heroes, the troubles don't stop coming and he stays quite busy, ending his described career involved with international terrorism and hijacking.
When we are first introduced to Speer, he is 46 years old but he looks at least ten years younger. He is an impressive figure, standing 6'1 1/2" and weighing 220 lbs, none of it fat. "His head was covered with close-cropped, Swede-yellow curls with a touch of gray at the sides, the bright thatch startling in contrast to his deeply-tanned skin. He has deep-set blue eyes and a flat nose. His chin is normally set in a stern, resolute manner and has several scars put there "by fists and other implements of combat."
Speer likes the occasional drink and the occasional beauty at his side but even more, he likes a good, tough case to get in the middle of and hammer his way out. He thinks with his brain, not his fists, but he lets his fists do the explaining on more than one occasion.
Since he enjoys a top-secret clearance and the respect of his bosses, it is Speer who gets pulled in when the case involves enemy agents or looks like it might. He is respectful to senior personnel but he never, ever steps back from a confrontation no matter who pulls what rank. He knows that many a crime has been covered up to protect someone's reputation or career and he is not one to let that happen when he is around.
Retirement does not slow him down when it comes to excitement and danger - it just dresses him differently.