Such is the velocity of history in the 20th century that decades become subjects for nostalgia barely after their passing. The '60s already seem ancient, the '50s antediluvian; even a film on the Watergate era, not yet a decade removed, seems a period piece. No decade passed more quickly into the realm of folklore than the 1920s, which Frederick Lewis Allen looked back on sentimentally from the close range of 1931, reminiscing about, almost literally, "Only Yesterday." A half-century later, despite the glut of more recent nostalgia, the '20s retain a special fascination, and now, with Geoffrey Perrett's new history, we have the most scintillating account of those turbulent years since Allen's classic.

Perrett is making a career of writing large-scale social history with epic themes. In "Days of Sadness, Years of Triumph" he examined the vicissitudes of life on the American home front during the crowded World War II years. In "A Dream of Greatness" he chronicled the postwar generation's headlong quest for personal and national fulfillment from V-J Day to the Kennedy assassination in 1963. In "America in the Twenties" he explores the tension between a fading but still feisty Victorianism and an ascendant modernism.

The '20s, of course, have long been characterized as a watershed decade in which old and new cultures collided: babbitts vied with Bohemians; Bryan and Darrow contested the relative merits of the age of rocks and rock of ages; custodians of the old order Henry Ford and Herbert Hoover were Puritans in a Babylon that they themselves helped create with new marketing and engineering techniques. Perrett's considerable accomplishment is to give this tired theme new vitality. With original insights and recycled materials, he introduces a fresh array of rural-urban counterpoints and crosscurrents: Bat Masterson and Wyatt Earp collecting spectators' guns and knives at the gate to the Dempsey-Willard fight; the last farm on Manhattan being converted to a miniature golf course; farmers in a small town protesting the removal of hitching posts and watering troughs from streets to accommodate automobile traffic.

Nostalgia buffs need not despair. Perrett retains the familiar '20s bench marks. Sacco and Vanzetti, Teapot Dome, raccoon coats and bathtub gin, flappers and Freudianism, Lucky Lindy, Tilden and Ruth, mah-jongg and crosswords, Chaplin, Capone, the Scopes Trial -- all the stock characters and happenings of the decade are recreated, again often with some new wrinkle or arresting detail. The supposedly aloof President Coolidge once shook the hands of 1,900 White House visitors in a 34-minute period. Hoover, despite his reputation for inaction, was diligent and decisive--the first president to place a telephone on his desk. A failing Woodrow Wilson is depicted as "a crotchety, embittered invalid," while Harding is portrayed (in an overdrawn assessment that rehabilitates "Uncle Warren" even beyond the current revisionist trend) as not merely genial and well-mannered but a workaholic and closet progressive.

Perrett laces his account with trivia that amuses as well as informs. New Yorker magazine founder Harold Ross drank cold drinks through a napkin because they hurt his huge front teeth. Teapot Dome conspirator Harry Sinclair, "the richest person ever to be imprisoned in the United States," while in jail slept in pink silk pajamas and had his laundry sent to New York by courier. A down-on-his-luck Frank Lloyd Wright was dropped from "Who's Who in America" in 1929. A sample tidbit: Between 1885 and 1914 there was not a single daylight bank robbery anywhere in the United States (banks were robbed, but at night); by 1928, with the introduction in the '20s of time locks and alarm systems that put after-hours safecrackers out of business, 1,100 bank holdups had already taken place.

For all of Perrett's milking of the decade's antics and escapades, this is a serious-minded book. Linking the minutiae, anecdotes and pen portraits are in-depth treatments of the literary scene, factory and farm, the politics of normalcy, the condition of women and blacks, economic developments leading to the Depression, and the origins of American institutions from General Motors and RCA to jazz and consumer credit. Perrett's research is impressive, as evidenced by about 40 pages of notes reflecting a remarkable range of sources and an extensive bibliographical essay. His work is as sturdy as it is lively.

Indeed, if there is a fault to this fine volume, it is that Perrett sometimes takes his subject, or himself, too seriously. "America in the Twenties," like his previous efforts, occasionally lapses into pretentiousness, so intent is Perrett on giving some unifying motif to the kaleidoscopic fragments of his social history. In "Dream of Greatness" he very nearly contrived a false theme, exaggerating the idealism and singleness of purpose of the post-World War II generation. Here he belabors a familiar one -- that World War I was "the death agony" of the 19th century. Even Allen in his 1931 work described the '20s as "the Indian summer of the nineteenth century." His new twists notwithstanding, Perrett develops the theme as if he invented it.

One might argue, finally, that Perrett may not even be correct. As Henry May has shown in "The End of American Innocence," in many respects it was the prewar decade that was truly the pivotal period in the cultural transformation of America, when cigarette consumption had already increased 500 percent (attributed more to mechanization of the tobacco industry than any change in mores), sleeveless gowns and transparent blouses were commonplace among fashionable women, and the sexual revolution was already in full swing.

Or a case may be made for the 1890s as watershed: Henry Steele Commager has noted, for example, the marked contrast in style and manner between the pre-1890s presidents and the clean-shaven, defrocked, business-suited McKinley. Certainly the process was an ongoing one; cultural schizophrenia was not confined to -- nor necessarily even centered in -- the '20s.

Such criticism should not detract from a thoughtful, vibrant, richly entertaining work. To those who would say that even nostalgia isn't what it used to be, try putting down Geoffrey Perrett's book.