Jack Gannon is an instructor for Delta Force.
Jack Gannon has put in his time in the Special Forces. Following several tours in Vietnam, he volunteered for the new military group known as Delta Force, being a founding member of that highly skilled organization. He saw action in several campaigns and won a fair number of medals and commendations for it.
He was good. So good, in fact, that upon his retirement from the military at age 40, he was offered a very rare position as a civilian training instructor for the clandestine infiltration group. This kept him in contact with his former teammates, a fact that would be of use to him in the recorded adventures. It is almost certain he would have lived the rest of his life in peace, content to train the young men who would go into harm's way, had not his life taken a sad turn.
A sadistic operative for the KGB decided to grab an innocent woman off the streets of New York, brutally rape and murder her, and toss her battered body onto the streets like so much refuse.
That woman was Jack Gannon's wife, visiting her mother in Manhattan. When the search for and punishment of the animal that took her from him did not come close to what he expected, Jack Gannon is forced back into action.
Very much a man of action, Gannon has little interest in the niceties of diplomacy or the rules of spycraft. When told the murderer almost certainly had diplomatic immunity, he shakes his head and replies coldly, 'Not from me.'
The actions he took in the first book brought him to the attention of the Intelligence community who then knew who to call when another impossible case came along.