It is a truth universally acknowledged that a popular story in one mode had better be adapted into others as well. Thus, novels are regularly adapted into movies or plays, and movies or plays into each other, the journey usually proceeding from page to performance, rarely backward.

So it's no wonder that Jane Austen's evergreen, 1813 comic novel of love and morality among the gentry, "Pride and Prejudice," which has often enough been adapted to the screen, is now on stage.

In the hands of Pittsburgh Irish & Classical Theatre, it arrives very handsomely as "Pride & Prejudice," centered securely on its spirited, flashing-eyed heroine, Elizabeth Bennet. The result is opulent and entertaining, with the droll comedy of the good-hearted but poorly parented Bennet family at the fore. But the transition is not seamless.

The problem is not the size of the story: this is not one of those three-volume Victorian epics, and adapter Jon Jory has compressed it efficiently by focusing resolutely on Elizabeth. But the great joy of the novel is Austen's narrative voice, commenting with wit and compassionate insight. How to preserve that?

You can't, although Jory does work some of Austen's witty asides into the dialogue, and others we can guess at as we watch machinations undercut or gone awry. As for the novel's famous first sentence about any man of good fortune's needing a wife, Jory assigns it to a Bennet family chorus, letting them express directly what Austen gently mocks.

That first sentence comes about five minutes into the play, because Jory starts by having Mr. Bennet introduce his family. That's uncharacteristic for him but in the popular mode of "Nicholas Nickleby" in which characters turn narrator.

This device and ruthless pruning enable the story to move very quickly. "There is to be a ball," someone says, and the next instant all are dancing. I admire this fluidity, but the audience better pay attention -- there are a couple of transitions so quick it felt like the Reduced Shakespeare guys did the compressing.

An inattentive audience might also be confused by some of the doubling, mainly that of Theo Allyn as Mary Bennet and Elizabeth's friend, Charlotte, and of Michael Fuller as Mr. Bingley and Mr. Darcy's other friend, Col. Fitzwilliam. The first case explains why the family is so often without funny, bookish Mary and perhaps why Charlotte is so curtailed. The latter is problematic because the two men are costumed so much alike.

Charlotte's curtailment is also because Jory downplays the novel's somber truths, including her being forced into a loveless marriage by financial necessity and the bad parenting by the disengaged Mr. Bennet.

The play's center, however, is richly rewarding, thanks to Leah Curney's lively, intelligent Elizabeth, who tells her own story so well that we rejoice in its happy outcome. David Whalen plays Darcy with such stiff hauteur it's hard to see why Elizabeth would love him, and in pursuing the comedy of men behaving awkwardly, Jory doesn't let him show the intelligence that would attract her. But we like him for her sake and together they make clear the triumph over his stiff pride and her sentimental prejudice.

Erica Highberg is appealing as the impossibly sweet-natured Jane, and Fuller is delightful as her destined match, the equally sweet-natured, air-headed Bingley. Joel Ripka is a charmingly devious Wickham, though I wish I saw a flash of opportunism. Laura Lee Brautigam is funny as the flirtatious Lydia -- Jory downplays the seriousness of her indiscretion, as well.

The fools are well handled, with James FitzGerald a delectable mix of obsequious and ostentatious as Mr. Collins. Linda Kimbrough is a proper gorgon as Lady Catherine, with a fine cameo as a housekeeper. And Lisa Ann Goldsmith is no fool as the decorously scheming Miss Bingley, balanced by her shrewd Mrs. Gardiner.

Mr. Bennet is forgiven his moral laxity partly because Philip Winters gives him too jolly an air, but he still scores his deadpan wit. Dixie Tymitz, who came into the cast late to play Mrs. Bennet, is a comic wonder of misplaced enthusiasm, like an effusive, pink-bowed bulldog.

Directing with authority is Scott Wise, who manages the many instantaneous scene changes with dispatch. Gianni Downs provides a handsome unit set of facades, which shift from exterior to interior as lit by Cindy Limauro. The greatest visual pleasure comes from Pei-Chi Su's elaborate period costumes.

The entire play, or nearly so, is accompanied by a pretty score by Douglas Levine, played by a live trio. But pretty is as pretty does. The music is essential for the many balls, but I found its overuse as underscoring really irritating. I could cite a half-dozen scenes where the music provides a gooey undercurrent that is at odds with the crisp precision of Austen's dialogue.

That's one lily that needs no gilding. But even with the ampersand, "Pride & Prejudice" is a treat.