The Cosmopolitan Country Boy : The New Yorker and its founder fabricated nostalgia for a world forever in evening dress : GENIUS IN DISGUISE: Harold Ross of The New Yorker <i> By Thomas Kunkel (Random House: $25; 496 pp.) </i>

Founding a magazine is like starting a marriage. You always forecast grand success, but often the mismatch is fatal and ends in catastrophe.

Magazines are trickier than marriages, however, because several types of romance must blossom simultaneously. One is the match between founders and investors, since all magazines cost more than predicted. Another is the essential bond between editor and writers. The third, and possibly most important, is the match between the magazine and the spirit of its time.

Our best magazine of the early part of the century, the iconoclastic The Masses, from 1911 to 1917 home to John Reed and other eloquent dreamers, was the voice of an optimistic generation not yet sobered by the full results of World War I and the Russian Revolution. Similarly, a big success today is The American Spectator; its habit of never letting the facts get in the way of the story is the perfect expression of a political generation trying to balance the budget by cutting taxes and keeping military spending high.

Thomas Kunkel’s gracefully written “Genius in Disguise,� a dual biography of the first 25 years of The New Yorker and of its talented founder, Harold Ross, makes clear how much that magazine, too, was a creature of its time. Its foppish air, with a hint of ironic distance, was embodied in the drawing on its first cover of Eustace Tilley, the high-collared dandy examining a butterfly through his monocle. This jaunty tone embodied the year of The New Yorker’s birth, 1925. To those Americans wealthy and literate enough to read a new sophisticated journal, the ‘20s were a time when there was plenty of whiskey in the speak-easies and plenty of money on Wall Street. Theirs was a world, like the characters of Peter Arno’s cartoons, forever in evening dress.

The new publication survived the charmed decade of its birth, however, because even when the bubble burst and our streets filled with bread lines, the magazine’s readers felt nostalgic for the vanished ‘20s. And so on The New Yorker’s cover, Eustace Tilley stared haughtily through his monocle on the magazine’s anniversary each February. Kunkel points out that the events by which we remember the 1930s--the Depression, the war in Spain, the gathering Nazi storm clouds--got much less space in The New Yorker than cartoons and theater reviews. The magazine ran a healthy profit throughout the decade, a rare feat for any American business at the time.

Some other happy matches Kunkel describes are familiar from countless memoirs, such as that between Ross and his unparalleled stable of writers. Some of these, like Edmund Wilson and Lewis Mumford, now seem better than ever; others, like E. B. White and S. J. Perelman, today feel dated; still other Ross mainstays, like Alexander Woollcott and Wolcott Gibbs, we’ve completely forgotten. Ross gave his best writers the feeling that their every word was weighed, considered and appreciated.

In the long run, a person can be a great writer or a great editor, but never both. Ross’ ego was invested not in his own prose, which he largely stopped writing after he began The New Yorker, but in making others’ shine. They knew it, and gave him their best.

A less familiar match is the odd one between Ross and his principal financial backer, Raoul Fleischmann, heir to the Fleischmann yeast fortune. To his credit, Fleischmann never meddled with editorial policy. But the two men had a complex series of quarrels over money and for many years did not speak. With offices on different floors of the same building, editor and owner communicated only through intermediaries, like the members of some crazed household in a story by the magazine’s own James Thurber.

Kunkel pays far too little attention to another match, that between The New Yorker and its advertisers. Several things underlay this romance. One was The New Yorker’s unusual design: all text, cartoons and illustrations were only in black and white. Hence ads in color (for which any magazine can charge a higher rate) stood out with great prominence. Furthermore, again most unusually, Ross’ New Yorker used no photographs. No pictures of Hoovervilles or Spanish war refugees marred the eye-catching parade of furs or evening gowns from Saks, B. Altman’s and Bonwit Teller, or automobiles from Pierce-Arrow.

Finally, although Ross won great praise for publishing John Hersey on the Hiroshima bombing, or Richard Rovere on McCarthyism, advertisers surely noticed that the magazine’s targets seldom included big business. During Ross’ lifetime, the promise made in the new magazine’s prospectus, “It will hate bunk,� almost never encompassed bunk peddled by American corporations. There was, after all, an honorable tradition of corporate muckraking by American magazines, pioneered by Upton Sinclair, Ida Tarbell and others around the turn of the century. But it was one that New Yorker writers did not continue. (One rare exception was the magazine’s brilliant press critic, A.J. Liebling.) The New Yorker was an advertiser’s dream.

The most unexpected match of all was between Harold Ross and New York itself. The New Yorker presents itself as the essence of that city. In later years came the famous cover which spawned a thousand imitations, showing the world west of the Hudson River as ludicrously foreshortened. Even today, the magazine reviews museum exhibits and dance and theater performances, many of which will never be seen outside of New York, although the vast majority of New Yorker readers live in those frontier territories hundreds or thousands of miles beyond the Hudson. We think of the magazine as having always been edited by a coterie of native New Yorkers.

What a surprise it is, then, that Harold Ross, the founder, grew up in a Colorado mining town. Kunkel tells us how, as a boy, Ross delivered beer and groceries to saloons and brothels and was even injured in a stagecoach accident. His formal education stopped after the first two years of high school. No effete dandy with a monocle, he rode freights, played poker, was an itinerant newspaper reporter all over the West and bossed a construction gang on the Panama Canal. He fished with Hemingway, drank with detectives and vaudeville figures, ran through three wives and innumerable other amorous liaisons, and, like Lyndon Johnson, received visitors at home in his bathrobe. He never lived in New York until he moved there only half a dozen years before starting the magazine.

In both a writer and an editor, a stranger’s eye is often the keenest. After all, Dickens was not born in London, nor Balzac in Paris, nor Robert Frost in New England. A man from the provinces, Ross created the greatest literary voice of the nation’s cultural capital. And, for all its flaws, he created something that grew and deepened. In the last years before his death in 1951, Ross found himself editing, at the dawn of the Atomic Age, a serious magazine for a deadly serious world. Moreover, the measure of any marriage is its descendants. Ross’ creation survived him, and some of its greatest achievements--the exposes of the Vietnam war and the Nixon presidency edited by Ross’ longtime protege and successor William Shawn--came long after his death. In the transitory world of journalism, few can claim such a legacy.