Whatever its shortcomings — including a sharply polemical tone throughout and an occasional failure to differentiate between the democratic left and its totalitarian variant — “A Conservative History of the American Left” by Daniel J. Flynn (Crown Forum, 464 pages, $27.50) is a remarkable compendium of American utopian and collectivist follies. Its greatest strengths lie at 30,000 feet, where generalizations about the left’s ideals and delusions concerning the creation of heaven on earth are spot-on, and, moreover, observable across the whole of the nation’s history. When it fails, it is in the details, especially with regard to the significant role played by some liberal Democrats in exposing and opposing Soviet Communism.

A bonus for conservatives: Mr. Flynn’s frequent, even relentless, forays into the dirty laundry of some of liberalism’s dearest icons. We learn that Planned Parenthood’s founder, Margaret Sanger, once spoke at a Ku Klux Klan rally and was a lifelong advocate for not only planned, but “selective” breeding, and that utopian planner Robert Owen pointedly excluded blacks from his failed experiment in New Harmony, Ind. Even though some of them finally woke up and snapped out of it, periodicals the Nation and the New Republic, philosopher John Dewey, and social worker Jane Addams served as megaphones for Lenin’s early brutalities. And the beat goes on. Later, the New York Times couldn’t find a famine in the Ukraine under Stalin.

The recurring themes in this history of the left as a fundamentally naïve political movement are easily summarized: a passionate commitment to the perfectibility of society; a failure to learn from, or even acknowledge, past failures in the perfection-building process; a devotion to the state and its coercive role in the utopian enterprise; a grotesque tic for the latest faddish salvation — whether it be eugenics, colonic cleansing, open marriage, the orgone box, LSD, phrenology, or cold water cures — or the reflexive, uncritical veneration of the natural world and its nonhuman inhabitants.

The poet T.S. Eliot once referred to such enthusiasms under the rubric “After Strange Gods,” and Mr. Flynn eventually ties the left’s deepest yearnings with the rejection of the deity. But he also points out in one of the more interesting sections of the book that it was not always so. “Utopian and collectivist ideas are as American as Plymouth Rock,” he notes, detailing the abolition of private property and the pooling of Pilgrim resources. Ironically, this radical step was imposed on the religious folk by their capitalist investors, who feared that private greed would eat at their profits — a reminder, as if we needed one, that corporate interest is not the same thing as free enterprise. But the Pilgrims eagerly embraced the concept for three years with predictably disastrous consequences. Finally, the colony’s first governor, William Bradford, parceled land to families for private use, rather, in his words, than that they continue to “languish in misery.”

Buttressing his argument that those on the left often ignore the failures of the past, the better to naively endorse far-fetched social projects, Mr. Flynn provides a detailed history of religious Americans who contributed to the creation of would-be utopias, from the Shakers to the Rappites, to the Oneida Community of John Humphrey Noyes. The rupture between religion and the left begins, interestingly, with the emergence of preachers of the Social Gospel, a largely Protestant movement allied with progressive reformers at the turn of the 19th century. A leading example was Jane Addams and her Hull House in Chicago, a pioneering institution for volunteer social work among the poor. As Mr. Flynn sees it, it was here and in similar venues that the Social Gospel became more social than gospel, and soon its advocates had little interest in the actual Gospel.

Mr. Flynn’s basic arguments are most persuasive when he is closest to his thesis that the project of perfecting society is not only fundamentally flawed, but antithetical to the concept of our nation’s founders that man is not an angel but a fallible creature whose ultimate happiness depends on appropriate checks and balances. His most telling anecdotes involve the terrible damage done by well-meaning liberals who thought they knew better.

The book veers off track later in the telling when it belittles or even ignores some of the well-documented efforts by mainstream liberals and even a few on the extreme left to unmask and resist the Soviet menace. Elements of the American Federation of Labor, for example, were far more critical to the defeat of that empire than a number of professed capitalists who defended the Kremlin to protect their sales of soda pop and the like. Moreover, the book underestimates the left’s positive contributions, particularly in the area of civil rights, where many conservatives had a less than stellar record.

Nevertheless, “A Conservative History of the American Left” is a formidable piece of work — a synthesizing popular history that deserves an audience wider than its polemical title suggests.

Mr. Willcox, a former editor in chief of Reader’s Digest, lives in Ridgefield, Conn.