WILD OATS, by John O'Keeffe. Directed by Leonard Peters; scenery by Russell Metheny; costumes by Hilary A. Sherred; lighting by Richard Winkler; music by William Penn.

With Ralph Cosham, John Neville-Andrews, Stephen Lang and Cara Duff-MacCormick.

At the Folger Theatre through Jan. 20.

As we press forward into this season of good cheer, our theatrical producers are reaching further and further backward in quest of appropriate entertainment. Who would have thought that, having depleted such happier-go-luckier eras as the '20s and the '30s, they would come up with their richest haul in, of all Godforsaken decades, the 1790s?

Goldsmith, you will remember, was dead. Sheridan had gone into Parliament, which amounted to the same thing. Over in Germany, Goethe, as ever, was rewriting "Faust," but it would never prove to be particularly happy holiday fare. In France, not only was the theater sleepy, but political circumstances were turning down-right hostile to light entertainment. p

But all this while, the Dublin-born John O'Keeffe was writing comedies that would delight his contemporaries and their progeny for another century or so. Our own century lost track of him, and was much the poorer for it until 1976, when the Royal Shakespeare Company found and produced "Wild Oats." And now, to Washington's good fortune, the Folger Theatre Group has done the same.

First produced in 1791, "Wild Oats" is a farcical ode to the theater in general and Shakespeare in particular, as represented by a touring actor called Jack Rover. Wherever Jack goes, even among Quakers for whom the theater should be abhorrent, the people who meet him are suddenly, totally and forever stagestruck.

At the Folger, to make the good news complete, Jack is ably played by John Neville-Andrews (star of last year's "Whose Life Is It, Anyway?"), and he is in excellent company.

"Wild Oats" is an audacious play, so full of complexities and coincidences that W. S. Gilbert might have blushed to behold them -- well, almost.What it wants and gets from director Leonard Peters is an equal concern for bravado and nuance, boldness and grace, to give the farce its deserved depth. Peters, like O'Keeffe, is new to Washington. The city should hold on to both of them.

Where to begin with the plot? Perhaps back when Sir George Thunder, before his retirement from the sea, forced a common young women into a sham marriage, left her with child and abandoned her.

Another marriage followed, with another son, Harry.

As the play begins, Harry has adopted an alias and, unknown to his father, gone on the stage under Jack Rover's inviograting infulence. Sir George's wealthy niece meanwhile, has taken a different detour from the path of family tradition by becoming a Quaker and, in the management of her estate, a mollycoddling liberal. She forgives her tenants everything, but immediately fires a gamekeeper for killing a fawn as it ate from his hand. "We should hate guile though we may love venison," she explains.

Although he disapproves of his niece's austere habits and her decision to disavow her worldly title as "Lady Amaranth," Sir George takes it in his mind to make a match between her and his son Harry. But when he dispatches his balet to find Harry, the valet finds Jack Rover by mistake, who, accepting this mistaken identity, falls in love with Lady Amaranth, and she with him.

This union of colorless religion and brash theatricality is the most audacious of O'Keeffe's audacities, and the human embodiemnts of those diverse sympahties are written -- and acted -- with great flair.

Neville-Andrews quotes Shakespeare in about the same unpredictable, effusive way Robin Williams quotes TV commercials. His enthusiasm for the theater is so irrepressible that he will make a speech in a rainstorm -- a rainstorm that involves real water too, as the Folger has staged it. Why did he abandon school, Jack is asked. "A truant disposition drove me from Wittenberg," he replies instantly. And whether quoting or extemporizing, he is always steeped in histrionics. "That face," he proclaims on meeting Lady Amaranth, "is a prologue to a play with a thousand good acts."

When she, believing him to be her cousin, remarks that "our families have long been separated," Jack's retort is delivered half aloud and half aside. "They have," he says. "Since Adam, I believe."

Cara Duff-MacCormick, as the object of his love, yields to his profane occupation with a delightful dispatch, and is soon ready to go on the stage herself. As the real Harry explains it, people of high birth are often tempted by the theater -- "A good part in a play is the first good character some of them have ever had."

Among the rest of the cast, Ralph Cosham is an amiably gruff Sir George, and Mikel Lambert (who just finished directing "Macbeth" at the Folger) has a magnificent turn in the small part of Lady Amelia, whose one big speech is a mouthful -- one of the swiftest, neatest and funniest sortings-out of a complicated plot that ever was.

But there is really no call to name names, because the entire Folger company seems to have seized this juicy play with the unpremeditated eagerness of a puppy coming across a big old bone.