By Ruth Rendell

Scribner. 257 pp. $26

It’s a pleasure to report that Ruth Rendell, at the age of 82 and after publishing more than 60 books, has given us yet another gem. A pleasure but not a surprise, since Rendell (who is also Baroness Rendell of Babergh, CBE, a member of the House of Lords and a stalwart of the Labour Party) has for years, along with her friend P.D. James, been bringing new sophistication and psychological depth to the traditional English mystery.

“The St. Zita Society” is both a sex comedy and a social satire, of the “Upstairs Downstairs” variety, with a few murders mixed in for our added delight. St. Zita, if you’ve forgotten, is the patron saint of domestic servants, and Rendell’s story focuses on the masters and servants who inhabit Georgian mansions on one block of Hexam Place near Sloan Gardens in the heart of London. In an opening scene, several of the downstairs folk — gardeners, drivers, nannies and the like — meet at the corner pub to organize a St. Zita Society.

“The St. Zita Society” by Ruth Rendell (Scribner)

The meeting was called by June, who’s 78 and for 60 years has been the long-suffering companion of a woman who styles herself Her Serene Highness the Princess Susan Hapsburg, on the basis of a brief, early marriage to an Italian whose royal claims were almost certainly fraudulent. June explains to her puzzled young friends that the goal of their new society will be “the question of Henry’s human rights.” Henry, the young driver for Lord Studley, is empty-headed but blessed with a “marked resemblance to Michelangelo’s David.” His rights are supposedly violated because Lord Studley often keeps him waiting for several hours before they motor off to the House of Lords. Henry is horrified by June’s plan to assert his rights, since it would surely cost him his job.

In truth, Henry faces a more delicate human rights issue. He’s having a secret affair with Lord Studley’s mindless 19-year-old daughter, the Honorable Huguette, and is also servicing the lord’s wife, Lady Oceane Studley, who hastens to the handsome lad’s basement room when her husband is away, bringing vintage wine and voracious appetites. Poor Henry is terrified of the woman but fears that if he spurns her, she’ll have him fired. What’s a boy to do?

More shenanigans are afoot at the nearby home of Lucy and Preston Still. He’s an insurance tycoon; she’s a stay-at-home mom who’s having an affair with an actor in a popular television drama. The actor’s visits are facilitated by Lucy’s comely au pair, Montserrat, who ushers the actor in and out and keeps an eye peeled for the absent husband. For her discretion, she’s tipped generously by both lovers.

One of the pleasures of all this conjugal comedy is being reminded that, sex-wise, there’s nothing new under the sun. Henry’s affair with his employer’s wife and daughter recalls Warren Beatty’s hairdresser in “Shampoo,” although he went Henry one better by adding his rival’s mistress to his agenda. A scene when Henry must take refuge in the closet because Huguette’s mother unexpectedly arrives recalls a hide-in-the-closet scene in F. Scott Fitzgerald’s “The Last Tycoon.” A scene in which an unknown but amorous visitor climbs into Montserrat’s bed in total darkness inspires memories of the immortal “Good grief, it’s Daddy!” moment in Terry Southern and Mason Hoffenberg’s comic novel “Candy.”

We’ve seen all these antics before — we never tire of them — related by everyone from Aristophanes to the Marx Brothers and beyond. Let us note that in several scenes Rendell sends an “urban fox” scampering hungrily along Hexam Place. I take him to be a four-legged symbol of the relentless carnal urges that lead her feckless characters — along with most of humankind — to catastrophes of one sort or another.

It’s no surprise that several murders enliven this romp, since we know from the start that one Hexam Place gardener is a former mental patient who tried to kill his mother. Nor should we be surprised that an individual of far more lofty social status proves to be just as capable of homicide as the deranged gardener. It’s a tribute to Rendell’s undiminished skills that she makes the killings as farcical as the bedroom antics. As the novel ended, I imagined Rendell smiling and recalling a line from one of her literary kinsmen: “Lord, what fools these mortals be!”