Call ahead and reserve your tickets. The Harvard-Radcliffe Summer Theatre production of "Noises Off" is a crowd-pleasing slapstick hit. Michael Frayn's well-written farce within a farce is miraculously pulled--and pushed--off by a talented company in its final play of the summer.

The script is a Goliath of staging and timing, though a lightweight in the plot arena. It challenges the actors to pull their audience into the woes of a small-time theater troupe hauling a British sex comedy through the little theaters of America. As the tour wears on and their idiosyncrasies explode, the show reaches a fever of chaos which is only just broken by the close of the final curtain.

Jane Nichols' direction, with the undoubtedly invaluable aid of stunt choreography by Thomas Derrah, keeps the staging under control while allowing the cast to unleash the script's zaniness.

HRST's audience is dragged into the fracas from the moment they enter the Loeb Ex. They are presented with two programs, one to "Noises Off," and the other to "Nothing On," the frothy British comedy that the touring troupe intends to present. The audience, like the actors, plays dual roles as the chaos rises and "Nothing On" degenerates into "Noises Off."

"Noises Off" has a built-in safety net for any foul-ups: the audience is watching a play within a play. If the sound effects are off, the set tacky, the lines flubbed, the sardines late for their entrance, it can be blamed on the crazily inept production of "Nothing On," rather than the cast and crew of "Noises Off." Fortunately, HRST is more than capable of working without a net. The production, at least from the house, runs flawlessly.

The set, by David's Overcamp and Gammons, is painted in a delicate cousin of Pepto-Bismol pink, and follows the carefully upholstered chintz precedent set by "The Philadelphia Story" this spring. Sound, designed by Jane Shaw, is minimal in the Ex; but the set's window was never broken without a crisp effect. Dune Becker's lighting maintained a rosy comedy glow even when the situation looked dark for the cast.

The structure of "Noises Off" is three presentations of the first act of "Nothing On" at various stages of its production. The first act gives the audience an idea of its proper staging as the cast plows the disastrous final dress-cum-tech rehearsal like Sherman through Atlanta. Technical rehearsals are legendary nightmares, but this is the rehearsal to end all rehearsals.

Brad Rouse takes confident control of the role of show director Lloyd Dallas, a theater artist pragmatic enough to check his artistic aspirations at the stage door. In his exasperation, he summarizes his art for the cast as time marches on in their final rehearsal, "That's what it's all about, doors and sardines."

Lloyd leaves the troupe to return to New York, and the second act turns the set around to follow the show from backstage as the nowdirectionless tour drags on. Lovers' quarrels storm, the casts' peculiarities begin to wreck havoc and the troupe's tensions creep on stage. The final act returns to the front of the house to survey the results of three months on the road from the point of view of "Nothing On's" unwitting audience: a madhouse held together by the eternal delusion that the show must go on.

Jessica Fortunato throws herself into the brassy gold pumps of Dotty, the aging theater veteran whose career and savings ride on the success of the tour. Dotty, however, is all too aptly named. Her earnest but inept struggles with the comings and goings of the script's schools of sardine props become a running joke. While clinging to her borrowed British accent as the apple-cheeked housekeeper, she mightily struggles to keep them in line.

When yet another line involving the plates of sardines eludes her, Dotty bangs her head in exasperation and apologizes to the director in one of "Noises Off's" best lines, "It's just that it's like a fruit machine in there; I open my mouth, and I don't know if its going to come out three oranges or two lemons and a banana."

On Tuesday night, Fortunato slightly missed the timing of that line, but hardly missed a step the rest of the night, as her character tripped and staggered through the backstage intrigues of the show.

Michael Stone, as her jealous younger lover Garry, is a stand-out in a solid cast. Born a century too late for the stellar vaudeville career he deserves, Stone employs his expressive face and spectacular physical comedy skills as the libidinous real estate agent of "Nothing On." He makes two fantastic falls down staircases that would have taken Chevy Chase a wagonload of painkillers to endure.

Garry's inability, in the first act, to articulate or finish his thoughts with anything but a "well, you know," comes back to haunt him as "Nothing On" strays farther from its course. His vague gestures and unfinished thoughts, sweetly endearing in rehearsals, mark him as a hopeless ad libber, degenerating from his tag "you know" to a helpless "who knows?" by the third act when the play no longer resembles its script. Garry's realization of his plight is the image of very actor's nightmare as, sweat pouring down his face, he stares out at the beady eyes of the house in horror, his mouth gaping for the lines that simply won't come.

Jessica Walling's wide eyes equally express her character with their blank blue stare. Brooke Ashton is the company ingenue, who is as far from ingenious as the rest of the cast is from their script. Though Brooke is able to put aside her space cadet personality to become the perky Inland Revenue tax secretary of "Nothing On," she is too fragile to roll with the punches when the ride gets bumpy. Oblivious, she sticks to the script, blindly thwarting the others' efforts to ad lib in the face of disaster.

Walling, who won Harvard's version of the best actor Oscar, the Levi prize, before her graduation this spring, is excellent in a deceptively simple role. It is difficult to play perk and spaciness with depth and comedic timing. To Walling also falls the burden of illustrating the title of "Nothing On" by tripping and skipping over the stage for three hours as two characters clad only in what the housekeeper calls her "smalls." Let's not forget that this is a British sex farce.

Her companion in blondness is Aaron Zelman as Freddy Fellowes, a well-meaning method actor who can only be described as dumb. Zelman compels mention of the film version of "Noises Off." His characterization of Freddy is unmistakably like Christopher Reeves' in the same role. Freddy craves motivation for his every movement on stage, prompting Lloyd into a deadpan Freudian probe of Freddy's character's relationship with groceries.

Holding everything together is Belinda, played by Francesca Delbanco, the mother hen and company gossip. Delbanco's exaggerated facial expression seem slightly overdone it the first act, but serve her well in the second as the action moves to pantomime. Her clever miming allowed the audience to catch every word--and say it aloud for her. By the third act, Belinda is trying to lead the company out of the woods, improvising for the mentally and verbally challenged. Delbanco's gives a perfectly outrageous delivery of Belinda's efforts, summing up an entire scene by announcing loudly to the audience, while doggedly staying in character, "The main thing is that the income tax people are after us."

Belinda's exertions are not enough to save the show, or to keep theatrical institution Selsdon Mowbray on the wagon. Selsdon is the old dog who keeps a step ahead of the company, despite his intermittent deafness and propensity for napping. Ian Lithgow as Selsdon is yet another solid cast member as the troupe's elderly bane and balm. His Selsdon is undeniably aged, while carrying the confidence of endless theatrical experience on his stooped shoulders.

Katie Guillory and Mark Fish as Poppy and Tim, the silently suffering stage managers and "techies" of "Nothing On," are a genre immediately recognized by their counterparts behind sets all over the world. Lloyd, realizing that Tim hasn't slept for days preparing for their opening night, magnanimously sends him off to "rest" by doing the company tax returns. The program for "Noises Off" lists Heidi Curran as both stage manager and costume designer. One has to hope the techies of this show are more rested than those of "Nothing On."

Guillory and Fish are wonderful as the only members of the company who don't want to be on stage, yet constantly find themselves called to step in as the cast's backstage dramas absorb them more than their entrances and cues.

Poppy brings the house down when she is finally pushed over the edge at the end of the second act. Tim has his moment in the limelight when, called upon to understudy the drunken Selsdon, he finds himself one ofthreeburglars center stage reciting Selsdon's lines.

HRST nearly does the impossible in giving Frayn's script the dual-leveled comedic chaos it demands. "Noises Off" is a guaranteed evening of laughter, and ends the adventurous HRST season with a successful staging gamble. It is also the last chance Harvard audiences may have to claim recent graduates Fish, Guillory, Lithgow and Walling as their own before others discover them.