David Danning is a lawyer.
He is a very successful lawyer who, with his son, make up the partner of Danning and Danning, along with numerous associates and paralegals. His success, though, comes more from solving problems outside the courtroom than any legalese inside it as Danning's largest claim to fame is the ability to unravel strange and intriguing mysteries and get to the bottom of things fairly quickly.
The lawyer/sleuth, now probably in his mid 50's, is an impressive man even beyond his accomplishments as he stands 6'4" tall weighing 200 lbs, none of that fat. An expert in judo and jujitsu, he lives such an active lifestyle that he does not have time to get soft. When he can be prodded and cajoled by his secretary to take a job, he throws himself into it and goes where the evidence takes him, no matter how dangerous the locale.
Danning is still often addressed by his military rank of Colonel, a position he earned while fighting in World War II in the OSS. It is that success, followed by the reputation as a trouble-shooter that eventually brings him back to the attention of the Pentagon and moves him from handling mysteries and cons to handling cloak and dagger assignments. He does not stop being a lawyer but he does accept work from Military Intelligence, jobs which take him to the Far East and up against Communist China as well as the Soviets and the Vietnamese.
When he is not solving strange cases and barely staying alive, Danning enjoys women, golf, and most of all, bridge. He is an expert at all three but a master at cards. With his strong rugged good looks and friendly manner, though, he should also be considered a master with women, though official points are not recorded for those accomplishments.
The character of David Danning joins a small group of private investigator-style action/mystery series which started out as such in the late 50's and early 60's and then changed the flavor of the missions to become spy adventures in the mid to late 60's. Though Colonel Danning's exploits during the War are sometimes alluded to in the first few cases, the author does not make much of the past until the later stories.