Nostalgia can reflect failure of nerve, a flinching from an arduous present and a daunting future. But Jeffrey Hart's new book, "When The Going Was Good!" a recollection of life in the 1950s, is constructive nostalgia.

Hart, who teaches English at Dartmouth and helps edit National Review magazine, counters that decade's despisers, who say the '50s -- tailfins and all that -- revealed America's crassness. To the intelligentsia, Ike and America were "the bland leading the bland." To Hart, "Not since the 1920s had so much been happening, both in popular and high culture."

In high culture, certainly: in the '50s, New York's three baseball teams had these four centerfielders: DiMaggio, Mays, Mantle, Snider. Also enriching the life of the mind were distinguished novelists (Faulkner, Hemingway), poets (Eliot, Frost), theologians (Niebuhr, Tillich), and painters (Hopper, Pollock) who made Manhattan the art capital of the world.

As a freshman in Connecticut in 1958, I remember Manhattan just before the awful decline. But the retreat from the city began in the early '50s, out on Long Island, where Levitt & Sons was completing a new house every 15 minutes, and selling it for $7,090.

"Eisenhower's smile," writes Hart, "was almost a philosophic statement." Some persons who wanted to supplement the smile with conservative ideas were casting seeds on stony soil. The emblematic intellectual of the '50s, Lionel Trilling, had written in "The Liberal Imagination" (1949) that "Liberalism is not only dominant but even the sole intellectual tradition." There were, he said, no conservative ideas in circulation. But in 1953, Russell Kirk published "The Conservative Mind," and in 1955 William F. Buckley Jr. launched the magazine (National Review) that, a quarter of a century later, was the president's favorite.

In October 1951, Lucille Ball began television's first long-running "sitcom" (situation comedy). Soon Lucy was, er, "expecting." (CBS banned the word "pregnant.") Forty-four million persons watched the episode, "Lucy Goes to the Hospital," twice the number who watched Ike inaugurated the next day.

In 1953, Hugh Hefner, the Henry Luce of the skin game, launched Playboy. In 1957 -- not a moment too soon -- Searle pharmaceutical company launched Enovid -- "the pill." Three '50s books -- "The Kinsey Report," "Peyton Place" and "Lolita" -- suggested what was, increasingly, on America's mind.

A Memphis record producer repeatedly said: "If I could find a white man who had a black sound and the black feel, I could make a billion dollars." Then he found Elvis. In 1955, Bill Haley and the Comets recorded "Rock Around the Clock" -- "the 'Marseillaise' of the teen-age revolution" -- for the movie "Blackboard Jungle." Rock music was lastingly identified with youth unruliness.

I, like Hart, was a happy lad in the '50s, which have a roseate glow in my memory. But Hart does not really refute the most serious accusation against those years. It is that they were pregnant with the impulses that made the '60s so dreadful.

In his nicely named final chapter -- "From the Clock at the Biltmore to LSD" -- Hart acknowledges that "the great shift in style and emotion" was gestating during the '50s. While we were "meeting under the clock," Hart notes there was a mass market for books anticipating the '60s anxieties about the suffocation of individuality and spontaneity by social structures and pressures: David Reisman's "The Lonely Crowd" (1950), C. Wright Mills' "White Collar" (1951), Sloan Wilson's "The Man in the Gray Flannel Suit" (1955), William Whyte's "The Organization Man" (1956).

James Dean's portrayal of an "alienated" teen-ager in "Rebel Without a Cause" (1955) caused a run on red nylon jackets, and popularized the kind of pouting that self-absorbed youths in the '60s confused with politics. A decade before Leonard Bernstein's cocktail party for Black Panthers gave rise to the phrase "radical chic," Bernstein romanticized juvenile delinquents by retelling Romeo and Juliet as "West Side Story" (1957).

Hart rightly emphasizes America's vitality in the '50s. But perhaps the going was good because the going was easy, and the standards of good were not demanding. We had unchallengeable military superiority, and settled for stalemate in Korea. We had an economic head start on a world recovering from war, and soon were panting.

The infantalism -- impatience, hedonism, inability to defer gratification -- that produced the cultural dissolution of the '60s helped give rise to the inflation of the '70s. Those failings gathered force in the '50s. Some of that decade's vitality was license -- a letting go after so much bearing down in Depression and war. The great release of energy in the '50s had a destructive dimension, reflecting a collapsing capacity for discipline.