The citizen of the title is actually Helm himself, who leads a happy and placid domestic life, married with children, a professional writer, mostly of westerns.

Being a professional writer of westerns is one of many details that locate the story quite firmly in the mid-century United States and there are numerous others.

One of the interesting things about the book is how Hamilton distilled of elements of men's adventure magazines and Mickey Spillane's I, The Jury and put them into what seems to be the classic power fantasy, that a character seemingly ordinary, everyday, banal, not particularly exceptional, just like pretty much all of us, in other words, is secretly, underneath, a dynamo of power, skill, knowledge, competence, etc.

It's similar to The Bourne Identity, but without amnesia.

Matt Helm belonged to a secret US organization in World War II. The organization had to be secret because its purpose was to help win the war and to hell with Geneva Conventions or anything like that. Their jobs were straight-up terrorism, torture, murder and so on.

In addition to learning all sorts ways to do these things, Helm also learned ruthlessness. You didn't become too friendly with your comrades because if one of them, say, got injured and couldn't execute the escape plan with you, you're not going to change the plan or leave them behind. The only practical option is to kill them before they inconvenience you any further, and Helm did this.

The hook of the story is that while at a totally normal suburban cocktail party, one of the most mid-century American events possible, fifteen years after the war has ended and Helm started living as a regular citizen, Helm is startled to see one of his former comrades walk in the door.

He's so startled that he momentarily forgets to pretend that he's never seen her before but she quickly and unmistakably signals him to remember his training, they've never met, she's working and so, now, is he.

From there the book is off and running and it's a real page-turner.

Hamilton handles everything very well, including an understated but very effective approach to violence. The tone is also quite witty, without undermining the tension of the plot or brutality of the actions.

Once Helm is reactivated he views the world of the "citizen" with a sardonic gaze, and is critically mocking of himself as well.

Too much wit would overwhelm the book and it would also be a distasteful affair without any. Hamilton has the perfect balance and also, by taking mainstream what's usually called something like men's adventure magazine fiction, happened upon a very successful formula. I'm really looking forward to reading the next one.