This is book 1 of the "John Clark" series.

This note contains spoilers for the book.

 

The origin story for Mr. Clark.

Basically, John Kelly has a run of bad luck with women. His wife dies, he picks up an escaped hooker and weans her off drugs and then they're ambushed on the way to a meeting with the police, and she's taken and killed as a lesson to the others.

He survives, and turns vigilante. In the end he's killed something like 10 people and busted up a major drug ring. Also he gets involved in CIA plots, and leads a mission to Vietnam to rescue prisoners that have been reported dead but are being held and interrogated. And turns up a major leak through a drug-using peacenik working for a congressman.

The book is showing its age. Several important parts of the plot don't work if people have cell phones, for example.

Kelly manages to get a new identity from the CIA, becoming Mr. Clark permanently, and arranges a boat accident in which Kelly is killed, with the police hot on his tail.

There's a lot of angsting over how the drug guys could be so evil as to torture people to death. Then Kelly tortures one of the drug guys nearly to death, to get information. It seems important to him that he doesn't quite kill the guy; he was still alive when dumped on shore. He isn't expected to survive, and he doesn't. And he seems to be easily capable of sorting out the truth from the lies.

Jack Ryan's father is a character, and Jack is referred to briefly.