“Heartbreak House,” opening tomorrow in a star-studded revival at the Roundabout Theatre, is just the show to put on when the world is falling off a cliff. If the timeliness of the play George Bernard Shaw subtitled “A Fantasia in the Russian Manner on English Themes” is not instantly apparent — and behind the façade of the period piece, it may not be — the source to consult is Shaw’s preface: 40-odd pages in 32 chapters under such headings as “War Delirium,” “The Wicked Half Century,” and “Those Who do not Know how to Live must Make a Merit of Dying.” What could all this have to do with an entertainment whose title promises dalliance and romance, and delivers in abundance?

Much of “Heartbreak House” unfolds like farce, but the realities behind it are deadly earnest. The play dates to World War I, supposedly the War to End War, but we know how that turned out. “To British centenarians who died in their beds in 1914,” Shaw wrote in 1919, when he set down the preface, “any dread of having to hide underground in London from the shells on an enemy seemed more remote and fantastic than a dread of the appearance of a colony of cobras and rattlesnakes in Kensington Gardens.” Until the terrorist attacks of September 11, 2001, our country basked in the same false security.

The action of “Heartbreak House” — not easy to summarize — revolves around the engagement of the penniless young Ellie Dunn (at Roundabout, Lily Rabe) to the ruthless industrialist Boss Mangan (Bill Camp), a lifelong associate of her father, Mazzini Dunn (John Christopher Jones), an incorrigible idealist. Ellie frankly intends to marry for money. Her new friend, the scintillating eccentric Hesione Hushabye (Swoosie Kurtz), will stop at nothing to torpedo the cynical misalliance. A madhouse party ensues. Swirling through, at fierce amorous cross purposes of their own, are a raft of other idlers, losers, and dreamers, principal among them Hesione’s sister Ariadne, Lady Utterword, a pillar of the colonial establishment (the incomparable Laila Robins), along with their aged father, Captain Shotover, Shaw’s cockamamie answer to King Lear (Philip Bosco, stepping into boots formerly worn on Broadway by Rex Harrison, Maurice Evans, and Orson Welles).

Chekhov filtered through Oscar Wilde — yet there also flows through “Heartbreak House” an undercurrent of apocalypse.The stage directions explicitly describe Captain Shotover’s home in the hills of Sussex as a ship, and it is no reach to construe it as the Ship of Fools evoked by Sebastian Brant in his runaway 15th-century best seller by that name (later appropriated by Katherine Anne Porter for her best-selling allegory of Nazism). Folly, in Brant’s pious allegory, is pretty much the human condition; the ship, accordingly, the world.The passengers are headed not for heaven but for a fool’s paradise — by inference, damnation.

If Shotover’s estate is a ship of fools, it is also — literally — a powder keg. The Captain is stockpiling dynamite; the remaining object of his attention is attainment of the “seventh degree of concentration,” which will allow him to detonate weapons by the sheer power of thought. “I will discover a ray mightier than any X-ray,” he announces. “A mind-ray that will explode the ammunition in the belt of my adversary before he can point his gun at me.” In Shaw’s surreal closing act, the mad skipper of his landlocked vessel apparently accomplishes that goal, for whatever good it does him or the world.

In the play, the note of prophetic warning sounds only occasionally; in the preface, it blares constantly, like an air-raid siren. Flip the pages at random: “I cannot pretend that I noticed either in the papers, or in general intercourse,” Shaw writes, “any feeling beyond the usual one that the cinema show at the front was going splendidly, and that our boys were the bravest of the brave.” He thunders at the way “the young, the innocent, the hopeful” were forced to expiate “the folly and worthlessness of their elders.” “Truth telling,” he says elsewhere,”is not compatible with the defence of the realm.” (Nonstandard orthography here and elsewhere is Shaw’s own.)

Shaw’s prescience in the preface feels downright diabolical: “Not content with the rancorous abuses of the existing law,” he declares, “the war maniacs made a frantic rush to abolish all constitutional guarantees of liberty and well-being.” (Guantanamo, anyone? Wiretapping?) He even foresaw 21st-century airport security. “Travelling must be stopped, or, that being impossible, greatly hindered.” No matches or lighters. No liquids or gels. And off with your shoes.

Shaw withheld “Heartbreak House” from the stage until the conflict that inspired it was over. “You cannot make war on war and on your neighbors at the same time,” he explained near the close of the preface. “When men are heroically dying for their country, it is not the time to shew their lovers and wives and fathers and mothers how they are being sacrificed to the blunders of boobies, the cupidity of capitalists, the ambition of conquerors, the electioneering of demagogues, the Pharisaism of patriots, the lusts and lies and rancors and bloodthirsts that love war because it opens their prison doors, and sets them in the thrones of power and popularity.”

These remarks are general, not specific to the play at hand. How Shaw’s global rage bleeds into his Anglo-Russian fantasia is easier to intuit than it is to explicate, even now. As noted, you cannot make war on war and on your neighbor at the same time.

“Heartbreak House” has never disappeared, yet it has never caught on. Are its prospects better today? Roundabout caters to an enlightened but retro subscriber base.Among the company’s specialties are the cutting-edge, “difficult” hits of yesteryear, lovingly recycled as escapism. Shaw lends himself easily to such treatment. When an offstage blast kills Boss Mangan, Hesione and Ellie hear the sound as pure Beethoven. Irony or not, the domestication of revolution can go no further.

Yet there are passages that refuse to dissolve into nostalgia. “She means that her heart will not break,” Captain Shotover explains at a crucial juncture, speaking of his proper younger daughter. “She has been longing all her life for someone to break it. At last she has become afraid she has none to break.”

Lady Utterword flings herself on her knees: “Papa,” she cries, “don’t say you think I’ve no heart.”

Shotover, raising her up with what a stage direction calls “grim tenderness,” answers: “If you had no heart how could you want to have it broken, child?”

Is it war — even war halfway around the world — that leaves a person so bereft, so numb, such a stranger to her inner life? Certainly in 2006 the malaise is not unknown. “Heartbreak House” speaks to its origins.