AMERICAN HISTORY IS the history of fitful enthusiasms. “On canal boats” in the nineteenth century, Gilbert Seldes records mysteriously in the history of American fanaticism that he published in 1928, which has been reissued by NYRB Classics, “bed-linen was promiscuous.” There were fads in fashion: “Men … wore the enormous cravats which had been introduced by George the Third to hide the swelling on his neck.” Fads in food: “Carrots were scarcely used and the tomato was known as the ‘love apple’ and considered poisonous”; and a little later, “[b]roccoli had been introduced and the tomato accepted.” Fads in propriety: “At Long Branch it was correct for two girls to go into the water accompanied by one man.” Even fads in perception: “Broadway, in New York, was considered more attractive by night than by day.” The litany continues: “The beard was an object of mockery.” “The rocking-chair was in.”

Lists of such fragmentary observations, which suggest the output of a hand-cranked steampunk search engine, are salted through The Stammering Century. Seldes’s book deals primarily with the slightly narrower—but nonetheless extremely diverse—fields of religious enthusiasm and political reform. The book’s intention, he writes, “is to connect these secondary movements and figures with the primary forces of the century.” Seldes wanted to show that there was a greater logic to the apparent cacophony of nineteenth-century enthusiasms—a figure in the carpet, to paraphrase that famous American stammerer Henry James. “The voices of the century seem at first a clamor of discords,” he writes early on, “but, if we listen carefully, we discover a certain relation between the major voice of progress and the minor voice of radicalism.” Moreover, the fringes of the nineteenth century “supply a background in American history for the cults and manias of our own time.”

In plenty of cases, though—and this, perhaps, was Seldes’s point—it is hard to separate the mainstream crazes from the “cults and manias”; previously commonplace items (like those “promiscuous” bed-linens) now appear as bizarre as the supposed oddities, or even more so. The nineteenth century’s most reviled “fanaticisms and eccentricities” included women’s suffrage, vegetarianism, and the abolition of slavery: those are not ideas that have gone the way of the cravat. In intellectual history, the relationship between figure and ground is always shifting, and what seems like madness or drollery to one decade will be the next one’s dogma or good sense. Given this consistent inconstancy, there may be worse ways to tell the story of our country than by tracking the notions that its citizens find ridiculous.

GILBERT SELDES CAME by his interest in wild ideas honestly: he was raised in an anarchist utopian community in Alliance, New Jersey, and though he subsequently tacked toward the Establishment—attending Harvard and serving as drama critic for the nonpareil high modernist little magazine The Dial—he maintained a ready sympathy for the lunatic fringe. His first (and most famous) book, The Seven Lively Arts, published in 1924, initiated the serious criticism of pop culture in the United States, declaring the greatness of Krazy Kat and Charlie Chaplin to a skeptical highbrow crowd. For his second book, he elected to inquire into the excitements of the past, and see whether or not they had extended beyond small circles of initiates.

Insofar as The Stammering Century has a master narrative, it is “the decline of the Calvinist theology brought over in the Mayflower” and the effects of that decline on the cultures of American belief. For Seldes, “nearly everything … of importance in the American mind of the nineteenth century … has its source in Jonathan Edwards,” the galvanic New England minister whose terrifying sermons (such as “Sinners in the Hands of an Angry God”) established a tone of extremity that generations of successors would attempt to match.