(Putnam/ )

Judging by my inbox, I’ve arrived at an age where Viking River Cruises thinks I’m in its target consumer group. Presumably, I’d fit right in with those silver foxes in the ads, lying prone on deck chairs, wineglasses in hand, gazing as the great cathedrals of Europe slide by. Some days, I’ll admit, it’s a vacation fantasy that has a certain appeal.

We aging boomers — and, statistically speaking, we boomer women in particular — are a growing market. Along with horizontal vacations, hormone therapies and discreet diapers, we’re also being attended to by a growing body of literary fiction.

But what about hard-boiled mystery fiction — the kind of book I’d be most likely to take on one of those river cruises? Are there any hard-boiled novels that speak specifically to us women of an age somewhere north of Nancy Drew and south of Miss Marple?

I became a devoted mystery reader in the 1980s, an era that was a veritable second Golden Age for feminist mystery fiction. Following the early lead of P.D. James’s “An Unsuitable Job for a Woman” (1972), British novelists such as Val McDermid and Liza Cody began to publish novels about female private investigators who pushed the boundaries of traditional gender behavior. In this country, both Sara Paretsky and Sue Grafton launched their series in 1982, following in the gal gumshoe footsteps of Marcia Muller’s Sharon McCone. (McCone’s first adventure, “Edwin of the Iron Shoes,” came out in 1977; her latest, “The Night Searchers,” was published in April.) The 1990s saw the arrival of Lisa Scottoline’s Rosato & Associates novels, about an all-female firm of lawyers who do double duty as sleuths, and the Alexandra Cooper series about a Manhattan sex-crimes prosecutor created by a renowned real-life Manhattan sex-crimes prosecutor, Linda Fairstein. Remarkably, almost all of these writers are still pounding the keyboards, which means that their female detectives are still pounding the pavements.

In my youth, I looked to these feminist detective novels for utopian images of women living autonomous, empowered lives. I’m still reading these novels for those rousing messages and images, but now I also want to know the answer to another mystery: How do these writers — who themselves have all entered the Viking passenger range — investigate the mystery of aging while female? How have their detectives kept their wits and reflexes sharp, and how do their series stay agile? In the past few months, Fairstein, Scottoline, Paretsky and Grafton have all published mysteries that might offer clues about whether aging with hard-boiled attitude is possible for female detectives and their fans or merely the stuff that dreams are made of.

At first glance, the news is discouraging: Most of these series seem to ignore the years going by. Fairstein’s smart, blond, thin and rich Alexandra Cooper has always been a fantasy made flesh, barely cracking a smile line in her 30-some-odd years. Her series is essentially backward-looking rather than forward-looking, because all the crimes take place at New York City landmarks: Grand Central Station, the Dakota, Central Park and, in her latest, “Devil’s Bridge” (Dutton, $28), the George Washington Bridge. Alex’s sidekick-recently-turned-paramour, NYPD Detective Mike Chapman (who, in a provocative twist, narrates most of the novel), is a history buff, and the glory of this series is that every installment offers readers an in-depth tour of the mysteries of New York City. Maybe Fairstein is giving us a stoic consolation about the passage of time through her series’s steady focus on the Manhattan cityscape: namely, that human life is brief, but great art and architecture endure.

Just as Fairstein shakes things up in her new book by keeping Alex Cooper offstage for a stretch, so has Scottoline experimented with ways of keeping her novels fresh. Scottoline took a long break from her Rosato & Associates novels to concentrate on stand-alone suspense tales like her most recent, “Every Fifteen Minutes” (St. Martin’s, $27.99), a terrific adventure involving a sociopath and the corporate shenanigans of big pharmaceutical companies. But Scottoline’s protesting readers convinced her that the “lady lawyers” needed to return. While, in general, Scottoline’s heroines seem frozen in time, it’s the senior characters on the margins of this series — particularly Mary DiNunzio’s parents — who tell us something about growing older with grace.

Scottoline’s message is that the pileup of years is bearable in the company of those you love, and that seems to be the same wisdom Grafton bestows in her latest novel, “X” (Putnam, $28.95), which features a smashing ending that rivals that of her debut, “A Is for Alibi.” Grafton has been allowing her PI, Kinsey Milhone, to age in tiny increments: She was 32 in “A Is For Alibi,” and here she’s all of 38. In Kinsey’s landlord and father figure, Henry Pitts, however, Grafton serves up a utopian vision of old age. Henry, along with his siblings, is in his 90s. Handsome, lean, gregarious and in possession of all his faculties, he is forever doing crossword puzzles and occasionally even serving as backup muscle for Kinsey when she’s chasing down crooks.

So far, these novels have been strong on fantasy and soft on female role models who age with grit. For a tougher vision of the toll the years take, we need to turn to Chicago, where Paretsky’s V.I. Warshawski is still plugging away, albeit with many more complaints about her “tired ­middle-aged legs” and much less sassy confidence in her ability to set the world right. In Paretsky’s superb latest outing, “Brush Back” (Putnam, $27.95), V.I. even sounds like a cranky old dame when she grouses about the weather in chilly Chicago, which she says is “no country for old detectives.”

It’s not exactly clear how old V.I. is these days, but she appears to be in her late 40s, early 50s. “Brush Back” is relentlessly nostalgic in that every aspect of its plot takes us back to her youth: Her faithless high school lover, now bald and burdened by beer fat, turns up at her office, asking for help in clearing his nasty old mother of a 30-year-old murder conviction. Also propelling V.I. back to the past is a visit from the goddaughter of her cherished late cousin, Chicago hockey player “Boom Boom” Warshawski, whose murder was the subject of Paretsky’s second novel, “Deadlock.” As the involved plot here about crooked politicians and construction contracts unfolds, V.I. gets threatened and beaten up; she also finds herself nearly drowning in memories of her old neighborhood and missing the friends who didn’t make it out.

V.I. has been growing progressively darker in mood as her series has continued, but throughout her bleakest times, work has always been her salvation; the new novel’s uncompromising feminist message about aging for women is to ignore the pain and hang on to what gives you purpose and identity. It’s a message of endurance that all of these long-lasting female mystery writers have exemplified in their own writing lives.

Maureen Corrigan is the book critic for the National Public Radio program “Fresh Air” and the author of “So We Read On: How ‘The Great Gatsby’ Came To Be and Why It Endures.” Michael Dirda is on vacation.