Spenser, the Boston private eye in Robert B. Parker's enduring series of hard-boiled novels, is the éminence grise of the genre - old enough to have fought in Korea and voted for Eisenhower. But is he showing any signs of decrepitude? Aside from finding 50-ish women attractive and needing a nap after lunch, the big lug doesn't seem to be slowing down. In Cold Service, he buddies up with his henchman, Hawk, and a posse of hard guys to bring down a gang of Ukrainians who have gained control of a town on the North Shore, from the corrupt mayor on down to the lowliest numbers runner, and are now angling to take over other rackets from established mobsters throughout the state - including some old friends of Spenser's.

The mob war is meticulously orchestrated, and the dialogue is precision-polished like a fine tool, which should satisfy Parker fans put off by last year's pallid ''Bad Business.'' But the rationale for Spenser's lawlessness and Hawk's violence is more complex than usual, and has a lot to do with the pressure on aging action heroes who can't afford to show, or even acknowledge, their vulnerabilities. The issue of mortality is on the table here, and Parker hasn't written as realistically or with as much feeling on the subject since ''Small Vices'' (1997), a series milestone in its candid portrayal of Spenser as the fallen warrior, forced to take a year out of his life to recover from the bullets of the hired killer known as the Gray Man and to confront his diminishing powers as a middle-aged man.

In ''Cold Service,'' the near death and rebirth of the mythic hero is experienced by Hawk, who takes three bullets in the back from a sniper and for six months suffers the indignity of being weak and helpless. ''I ain't supposed to get shot in the back,'' Hawk says. ''Ain't supposed to be like other men.'' But it's Spenser who articulates the code of honor that validates their murderous retaliation. ''I can't let somebody shoot me and get away with it,'' he explains to Hawk's unhappy girlfriend. ''I can't do what I do, or be who I am, if I'm afraid.''

So, do these guys learn anything from Hawk's brush with death? Hawk's answer is to heal as fast as he can and return to action as a leaner, meaner killing machine. The more introspective Spenser goes deeper into his friend's existential choices: ''If he changed he might cease to exist.'' Which is not to say that certain changes haven't crept into Spenser's work ethic. Although he still wrestles with his conscience, he's now more driven by his fear of mortality than by the old issues of morality. Looking for ways to shore up power, he's expanded his support group, making docile confederates of the very crime bosses he once battled. Through a tortured plot twist, even the Gray Man becomes involved in the scheme to force the Ukrainian mob from its stronghold. ''In what we do, there are no rules,'' this shadowy villain insists. ''We have to make some up for ourselves.'' Well, yeah. But they still have to make sense.

Marilyn Stasio, New York Times

Ultra-macho episode in long-running saga starring Boston shamus Spenser and his longtime backup man Hawk, involving loyalty, honour, courage and fortitude when Ukrainian gangsters who have taken over the small, corrupt town of Marshport murder a local bookie Hawk has been hired to protect and – unforgiveably – plant three bullets between his shoulder blades, missing his heart and lungs but leaving him at death's door.

Revenge is the medicine needed to restore him to full health and war is declared on the hoods and hooky lawmen who run the town. Help sought from unlikely sources including The Gray Man – who once tried to kill Spenser – and cops who put justice above the law. The ethics make you blink now and then, but the rougher the justice, the grittier the narrative. Exceedingly tough stuff, with Hawk standing tall on the last page and justifiable vengeance burning bright from start to finish.

Book of the year for your vigilante lobby but, rest assured, your conscience can take it. Thriftily written, with fewer jokes than usual, but grimly and consistently funny. It's the attitude that matters. Goes like a rocket too: amazing how Parker keeps up the pace.

Literary Review