There are a few simple prohibitions to remember when packing books for vacation:

Don’t take “Deliverance” on a canoe trip.

Don’t take “Into the Wild” camping.

And please don’t take Kate Christensen’s new novel on your next Carnival Cruise.

Trust me: Christensen is a discerning and witty writer, but “The Last Cruise” sails into such rough waters that it should come with a vial of Dramamine.

The story unfolds en route from California to Hawaii aboard the Queen Isabella, an elegant vessel built in France in the 1950s, “before cruise ships got put on steroids and turned into so-called ‘floating cities.’ ” Once the preferred ship of Natalie Wood, Marilyn Monroe and Gene Kelly, the Isabella is now on its final voyage. To celebrate that bittersweet retirement, everything on board has been carefully redesigned to echo its first cruise, to create “a theater of nostalgia,” with jazz bands, cabaret singers, old movies and black-tie dinners.

W ith no Internet connection to distract them, these 400 lucky travelers are free to glide across the Pacific entirely cut off from the modern world. “The forecast for the next two weeks held nothing but sunshine and calm seas,” which should immediately rouse your inner Hercule Poirot.

Into this tiny, floating world, Christensen introduces three characters — none of them paying passengers — who will experience the last cruise in radically different ways.

Miriam is a former Israeli soldier who has been playing violin in a string quartet along with her ex-husband since the mid-1970s. Like the Queen Isabella, she and her fellow musicians are getting old and don’t have many miles left. But the ship’s owner has long been the quartet’s sponsor and has graciously insisted they perform a piece called “Six-Day War” on the boat’s last cruise.

Far below deck toils a handsome sous chef from Budapest named Mick. Determined to break away from the sea and his promiscuous lover, Mick sees this voyage as a last-ditch chance to impress the ship’s executive chef and get a job at one of his legendary restaurants on terra firma.

And finally there’s Christine, a farmer from Maine who has accepted an invitation to tag along with an old female friend. Though only 36, Christine feels rural and frumpy amid this unaccustomed glamour. She can’t help noticing that all the other women’s bodies are “soft and unmarked and well nourished, somehow unformed, even the ones obviously honed in the gym, without a shred of wildness or aggression.” But what a relief to be away from the labor of the farm — and, frankly, away from her sweet husband, too, with his imploring requests to start a family. “We work hard on our own land, and it’s a good life,” she tells a fellow passenger, opening up the way one does to people you’ll never see again. “But sometimes I feel invisible. Like I’m disappearing.”

Having gathered these disparate people together, Christensen gently rolls and pitches the stage, dislodging stones of sadness that had been safely stuck in the crevices of their everyday lives. That discombobulation is the key to the story’s appeal, its unstable mix of romantic comedy, class oppression and spiritual angst — as though Cynthia Ozick wrote an episode of “The Love Boat.”

Christensen is a master at drawing us into the interior lives of her characters, toeing the line between satire and sympathy. She knows the comedy and humiliation of age just as well as the energy and anxiety of youth. Miriam and Christine would seem to be at very different stages of their romantic lives, but under the undulating motion of this cruise, both find themselves shaken loose from long-held assumptions.

And as Christensen showed in “The Great Man,” which won the 2008 PEN/Faulkner Award, she’s particularly astute about the conflicting selfishness and nobility of men. Mick enters as a lout on the prowl, but we quickly come to see him as a tortured romantic — and a highly skilled chef.

Indeed, as on any good cruise, this novel’s most sumptuous element is its lavish food. Christensen, who has published two foodie memoirs, “Blue Plate Special” and “How to Cook a Moose,” whips up page after page of delicious kitchen scenes, full of mouthwatering ingredients, scalding heat and athletic cooks “swathed in white like doctors, working silently as if they were saving and healing live bodies rather than cutting up dead ones.”

But as much as she revels in those delectable buffets, Christensen also deconstructs the aura of the cruise ship. These floating palaces are, as she demonstrates, grotesque microcosms of our stratified world. The atmosphere of ease and plenty aboveboard is maintained only by the tireless labor of mostly nonwhite people in the dark depths of the ship. As the Queen Isabella sails out across the ocean, the tension between those classes grows dangerously taut.

Although that geopolitical metaphor is convincing, it would ultimately make for a rather schematic and dull story. Fortunately, Christensen has something more mysterious and existential in mind. She’s interested in the most intimate and profound changes we’re willing to make only when tossed by the tempest of life. Near the very end of “The Last Cruise,” Christine laughs “with a jaunty hilarity that was completely at odds with their predicament.”

There’s a worthy model for us all on this unpredictable voyage — anchors aweigh!

Ron Charles writes about books for The Washington Post, where he hosts

The Last Cruise

By Kate Christensen

Doubleday. 304 pp. $26.95