Gregory Feeley, in the Weekly Standard (Sept. 6, 2004):

PART FICTION, part historical speculation, the publishing genre known as "alternate history" is a literary chimera--a seeming anomaly that is perfectly in sync with its time. Popularized by the Edwardians, alternate history pottered along for decades, mostly as a literary curiosity, before roaring to life in the 1990s, just in time for a century to which it seems peculiarly suited.

In form, alternate history draws upon the genres of science fiction and fantasy, historical novels and adventure stories, even technothrillers and mysteries--something from just about every contemporary publishing category, except "literature." It hasn't often broken into movies (explaining the setup seems inescapably to involve one step too many), but it has established itself not only on superstore bookshelves but in the popular consciousness.

Alternate history--in its early days, it was known as "counterfactual history"--first appeared in recognizable form not in fiction but as an exercisein popular essay-writing by genuine historians. The publication of G.M. Trevelyan's essay "If Napoleon Had Won the Battle of Waterloo" in 1907 is usually cited as the tradition's starting point, and Trevelyan certainly served as the inspiration for the 1931 anthology edited by J.C. Squire, If It Had Happened Otherwise, with essays by G.K. Chesterton, Hilaire Belloc, A.J.P. Taylor, Winston Churchill, and others. The piece's titles--"If the Moors in Spain Had Won," "If Louis XVI Had an Atom of Firmness," "If Byron Had Become King of Greece," and so on (Churchill, with some wit, contributed "If Lee Had Not Won the Battle of Gettysburg")--made clear that while "counterfactuals" might consider any possible variation in history, their appeal lay in imagining the different outcomes of important military campaigns. The frisson of political foreboding, with a dash of sensationalism, was present from the first.

But while Squire's volume was popular, the tradition goes back earlier. Trevelyan may well have seen the series of "Reviews of Unwritten Books," cowritten by the British eccentric Baron Corvo and published in the Monthly Review in 1903, which similarly toyed with history, and included a discussion of "Machiavelli's Dispatches from the South African Campaign." A year earlier, an American novelist named Charles Felton Pidgin published The Climax; or, What Might Have Been: A Romance of the Great Republic, which detailed the century of history following Aaron Burr's election as governor of New York and unbroken, duel-free climb to political power. This is alternate history in its purest form, although many of its elements can be glimpsed in a number of popular novels published in the United States, England, and France from the mid-nineteenth century (the 1836 Napoléon et la conquête du monde, 1812-1823 seems to be the first) and increasing in number in the 1880s.

None of this was regarded as serious literature or serious history, and most works of alternate history (no one seems to know when the term was coined) enjoyed brief shelf lives, reflecting as they did the anxieties of their own immediate era. Their staple theme continued to be the triumph of one of history's bugbears, with Hitler (who soon replaced Napoleon) and Robert E. Lee becoming by far the most popular. The frisson remained marketable (in 1960 Look magazine commissioned two essays by well-known popular historians to explore imagined Nazi and Confederate victories). But by the 1950s alternate history was largely confined to science fiction, which explored the possible themes in the genre's usual straightforward and rationalist manner. L. Sprague de Camp's 1939 Lest Darkness Fall, in which an American cast back to the sixth century A.D. attempts to prevent the onset of the Dark Ages, was an early and influential example.

THESE BOOKS were frequently engaging, and some of them, such as Philip K. Dick's The Man in the High Castle (1962) and Keith Roberts's Pavane (1968), possessed considerable artistry. But the ingenuity science-fiction writers lavished on their reconfigured histories was often naive, and their stories remained a distinctly local product.

The number of alternate histories published in science fiction nonetheless grew steadily through the 1970s and 1980s. A few examples appeared in the commercial mainstream, including The Court Martial of George Armstrong Custer by the well-regarded historical novelist Douglas C. Jones in 1976 (an early example of what would prove a salient commercial strategy: putting a famous historical figure in circumstances diametrically at odds with his historical fate) and Thomas Berger's 1989 Changing the Past. These books tended to present the concept of a novelist's changing history as itself a striking idea--which is an indication of how modestly the popular articles and genre fiction had penetrated general public awareness.

One can see this in the 1980 film The Final Countdown, which transports a present-day battleship, by some storm-induced time warp, into the Pacific a few days before Pearl Harbor. The crew is startled to realize that they can shoot down the Japanese attack and alter the course of history, and the audience is invited to be equally startled by the idea. In the film, a second storm takes the boat back before the sailors can act, which renders the disconcerting possibilities moot. Such an approach was typical of the time: The implication of alternate history--the foundation-dissolving notion of an unfixed past--was quickly followed by a retreat in the end to a reaffirmed status quo.

This changed abruptly in the early 1990s. The year 1992 saw publication of Fatherland by Robert Harris, an international bestseller, and Harry Turtledove's The Guns of the South, which has sold 350,000 copies over the past dozen years. Three years later Newt Gingrich and William Forstchen published 1945, which posits that Hitler was lying in a coma in December 1941, and so could not declare war on the United States.

All these novels were marketed to a much broader audience than had ever read alternate history before. Unsurprisingly, they all stick to simple deviations at well-known points of history--to the big two, in fact: Nazi Germany and the American Confederacy. Fatherland posits a victorious Third Reich, while 1945 dramatizes a World War II in which America's crucially delayed entry allowed a threatening series of Nazi developments....

THE HISTORICAL NOVEL in English, a nineteenth-century innovation, was judged in good part by the accuracy of its imaginative evocation: However attractive the edifice the novelist raised--and it was practiced by the likes of Sir Walter Scott, William Makepeace Thackeray, and Charles Dickens--the novel was thought unsound by the reading public if its historical basis was faulty. Even after the historical novel ceased (for various reasons) to be a candidate for "serious" literature and was demoted to the demimonde of popular "entertainment," the rules persisted: Lack of fidelity to the historical record was a flaw, excusable in Shakespeare but not in modern writers. The past was knowable, and one got it either right or wrong.

Old-fashioned writers of historical fiction were often attracted to the imaginative possibilities of what we would now call alternate history, but they also mistrusted it. Nathaniel Hawthorne justified his dramatization of Byron and Shelley living into old age in his 1845 story "P.'s Correspondence" by introducing a frame device that made his text the writings of a madman, and H.G. Wells explained away the alternate history of his 1905 A Modern Utopia by claiming that the story took place on a planet just like Earth but "beyond Sirius." The Modernists who followed the Victorians knew historical fiction to be, like fantasy and ghost stories, unsuited to serious literature.

Postmodernism's willingness to entertain notions that Victorian and Modernist alike would have frowned upon has given contemporary novelists almost complete freedom over their subject matter. The past is no longer fixed like cement: It can be played with. John Fowles's The French Lieutenant's Woman was, in 1969, the first historical novel in decades to be taken seriously as a work of literature, and by no coincidence, it exhibited a full set of what we now call postmodern characteristics.

But postmodernism is not the only element in the emergence of alternate history. The pressures of modern publishing have also helped, as alternate histories lend themselves almost uniquely well to what publishers call "high concept." The central idea behind most alternate histories is so straightforward as to be iconic--sometimes conveyed in the title, but often reducible to a single image, which publishers have been happy to employ. An early instance was Knopf's memorable dust jacket for Len Deighton's 1978 SS-GB, which showed, with perfect economy and clarity, a British postage stamp with Hitler's visage upon it, postmarked late 1941....

Writers of alternate history would bristle at the suggestion that they conceive their novels around the envisioned cover designs. But it is fair to suggest that the vivid, compressed, and electrically intense experience--the preview that gives you a speeded-up miniature of the entire movie, the three-minute drama on MTV--is popular today for the same reasons alternate history is popular: They offer not moments recollected in tranquility, but a rush.

BUT THERE'S MORE to the success of alternate history, for it is also a surprisingly adaptable genre. A children's book can be alternate history, and so can a mystery, or a spy novel, or even a romance. Jasper Fforde's The Eyre Affair is plainly alternate history--the setting is a 1985 in which the Crimean War has raged for 130 years--but it is also a detective novel, and a fantasy as well (the protagonist must investigate the kidnapping of Jane Eyre from the confines of her novel).

The loss of literature's sense of high mission has also helped alternate history. The novel has been wriggling free of its old moral prescriptions for the past hundred years, and cultural critics still willing to judge literature by how well it embodies Matthew Arnold's "grandeur of spirit" or F.R. Leavis's "maturity" are a dwindling rear guard. Once you accept that alternate history is not merely moral laxness about getting the facts right, you can enjoy the imaginative freedom it affords. One problem in reading, say, Frederick Forsyth's 1971 The Day of the Jackal (a thriller about an assassin stalking Charles De Gaulle) is that you know how it has to end. In alternate history, you don't....

If there is something troubling about the current vogue for alternate history, it does not lie exactly in the form itself or with any specific subject matter. But its defining tropes and conventions are the occasion for readers to retell to themselves their own favored stories, reinforcing personal narratives rather than finding in a text something new. The ethical imperatives of reading cannot be itemized, but one of them is certainly the obligation to acknowledge the real world that--in however complex and mediated a manner--profoundly informs even the most fantastical text. Alternate history, for all its pleasures, invariably brings with it the temptation to do otherwise.