Kate Beckinsale, right, plays Lady Susan and Chloë Sevigny, left, plays her best friend, a rich American named Alicia, in Whit Stillman’s “Love & Friendship,” an adaptation of a Jane Austen novella. (Bernard Walsh/Amazon Studios and Roadside Attractions)

Fans of Jane Austen (“Pride and Prejudice,” “Emma,” “Sense and Sensibility”) who also happen to be fans of Whit Stillman (“Metropolitan,” “Barcelona,” “The Last Days of Disco”) will probably have only one question on seeing “Love & Friendship,” Stillman’s adaptation of Austen’s posthumously published novella “Lady Susan.”

What took him so long?

This smart, stylish period romp, set among the manor born in England in the late 18th century, deftly grapples with the morals and mores that occupied Austen in so many of her books. Yet her titular heroine is far more troublesome and difficult to like than Elizabeth Bennet or the Dashwood sisters. Lady Susan Vernon is scheming, manipulative, ethically compromised and endlessly resourceful, where her fortunes and romantic prospects are concerned. This might make her dubious as a heroine, but it’s also an enormous amount of fun.

As portrayed by Kate Beckinsale — in a role that finally does justice not only to her serene, catlike beauty but to her skills as an actress — Lady Susan cuts a wide, heedless swath through the posh country homes of friends and relatives, who have been putting her up (and putting up with her) since the recent death of her husband. Ostensibly, she’s on the hunt for a suitable mate for her daughter, Frederica (Morfydd Clark), toward whom she harbors a thinly veiled resentment. In reality, she’s on the prowl for her own flirtatious benefit and ultimate profit, her quarry often — but not limited to — younger, helplessly besotted men.

Based on Jane Austen's novel "Lady Susan," the widowed Lady Susan Vernon (Kate Beckinsale) seeks refuge with her in-laws as rumors about her private life circulate through society. (  / Roadside Attractions)

Complications can’t help but ensue in a story that Stillman helps along with witty, onscreen text descriptions of the characters, including Lady Susan’s best friend and confidante, a rich American named Alicia (Chloë Sevigny). And the filmmaker shows just as much dexterity with the spoken dialogue, which trips off the actors’ tongues with such trilling, offhanded grace that viewers may not appreciate a bon mot until another plummy zinger has taken its place. Hewing to Austen’s original epistolary structure, “Love & Friendship” hits all the pleasure centers of a sumptuously appointed comedy of manners, with lots of tea, candles, damasks and brocades to cushion Lady Susan’s rampant — but always expertly camouflaged — amorality.

As lively, vivacious and intelligent as the reputation that precedes its lead character, “Love & Friendship” lilts along harmlessly until it delivers one of its many rapier-like observations, whether about parenthood, the provisional economic status of single women, the nascent, uncouth colony across the pond, or the ever-fraught subjects of its title. At one point, Lady Susan says Frederica’s school fees are “far too high to even think of paying.” Later, she conspiratorially describes Alicia’s wealthy husband as “too old to be governable, too young to die.”

The presence of such a shallow viper would feel unbearably cynical, were it not for the porcelain, put-upon Frederica, the generous in-laws off whom Lady Susan blithely sponges, and Stillman’s own judicious touch with a film that balances sharpness and escapism with admirable control. “Love & Friendship” is such a thoroughgoing delight that it’s tempting to riffle through Austen’s other works to find something else for Stillman to make into a film. As adaptations go, this is a match made in heaven.

PG. At area theaters. Contains adult themes. 93 minutes.