It would be hard to find a less compatible pair of great writers than Virginia Woolf and Walt Whitman. Woolf’s novels sharpen consciousness down to the finest of points, until there is nothing left but a constantly mobile noticing, a nervous evanescence; Whitman’s poems inflate consciousness to the size of the universe, avidly consuming everything and everyone in sight. Erotically, too, they are nearly perfect opposites, Woolf’s anxious chastity shrinking before Whitman’s cosmic adhesiveness. Surely Woolf would have found Whitman vulgar, and Whitman would have thought Woolf a snob.

It’s an impressive feat of readerly sympathy, then, that Michael Cunningham, whose last book, “The Hours,” was written under the sign of Woolf, should return with a novel equally soaked in the influence of Whitman. In a few superficial ways, “Specimen Days” (Farrar, Straus & Giroux, 308 pages, $25) is cast in the same mold as its Pulitzer Prize-winning predecessor. Again Mr. Cunningham borrows a title from his tutelary genius (“The Hours” was a title Woolf considered for “Mrs. Dalloway,” “Specimen Days” is the name of Whitman’s rambling 1882 memoir); again he offers three linked stories, thematically related but widely separated in time. Whitman is even a character in “Specimen Days,” though he plays a much smaller role than Woolf did in “The Hours.”

Mr. Cunningham, in other words, has invented a new genre for himself, lying at the crossroads of fiction, biography, and criticism. But it is a surprisingly flexible and capacious one, for “Specimen Days” is as different in spirit from “The Hours” as Whitman is from Woolf. Appropriately, if Cunningham’s Whitman book lacks the delicacy of his Woolf book, it also avoids the preciousness and ethereal sentimentality that made “The Hours” so irritating. Mr. Cunningham is not just repeating his success, but pushing himself into new territory: annexing the rude energies of genre writing, mussing his prose and his plots, at moments even daring himself to be preposterous. The result is a fascinating and peculiar book, which shuns mere artiness in favor of bold experiment.

Just how bold can be suggested by some of the more outlandish things the reader encounters in “Specimen Days.” There is a young boy with a Tourette’s-like disorder that makes him recite lines of Whitman at inappropriate moments; a female cult leader who calls herself Walt Whitman, and who trains abandoned children into a suicidal army; a cyborg implanted with a poetry chip that gives him encyclopedic knowledge of Whitman’s works. These three characters appear in the three novellas of “Specimen Days,” each of which takes on a different genre and a different historical period. What they have in common is a defiantly contrived obsession with Whitman: on every other page of the book, it seems, someone is reciting a spookily apposite line from “Leaves of Grass.” The effect is to restore to Whitman, so often banalized as the cheerleader of Americanism, something of his genuine strangeness, his unreassuring transcendence. The poet who wrote “to die is different from what anyone supposes, and luckier,” was beyond good and evil – as Mr. Cunningham reminds us when he puts these words into the mouth of a child suicide bomber.

Children and suicide, in fact, are the major elements that echo ingeniously through the book’s three sections. These themes, along with a New York setting and a recurring set of character names, make the stories of “Specimen Days” seem like a series of variations on a theme, or the stages of an eerie eternal return. In the first novella, “In the Machine,” set in the Irish ghetto of late-19th-century New York, a deformed young boy named Lucas is haunted by the ghost of his older brother, Simon, who was killed in a factory accident. Lucas’s guilty, idealizing love for Simon’s fiancee, Catherine, leads him to a terrible act of self-sacrifice.

The second story, “The Children’s Crusade,” set in the present day, gives us another Catherine – Cat Martin, an NYPD forensic psychologist, who has a boyfriend named Simon and a dead son named Lucas. Here, again, there is a deformed boy intent on redemptive violence, as part of a group of juvenile terrorists; in this pastiche thriller, Cat must try to locate the boy before he can detonate himself. Finally, “Like Beauty” imagines New York a few hundred years in the future, when the city has become a giant Disneyland for tourists, and menial labor is performed by a race of lizard-like alien refugees. Yet again, Mr. Cunningham gives us a Simon, this time an android, who is in love with a woman named Catareen, one of the despised Nadians; and again there is a misshapen boy named Lucas, who seeks redemption by fleeing the polluted Earth for greener planets.

All of these Catherines, Simons, and Lucases share a New York setting – the Lower East Side, the East Village, and the Bethesda Fountain in Central Park appear in each story – and the real, hidden plot of “Specimen Days” is the decline and fall of the city Mr. Cunningham loves. The one thing Woolf and Whitman have in common is their profound immersion in the metropolis. In “The Hours,” Clarissa Vaughan’s strolls through the West Village echoed Clarissa Dalloway’s excited exploration of London. And Whitman is, of course, the patron saint of New York flaneurs. As he wrote in “Broadway Sights,” a section of his “Specimen Days”: “I knew and frequented Broadway – that noted avenue of New York’s crowded and mixed humanity … Always something novel or inspiriting; yet mostly to me the hurrying and vast amplitude of those never-ending human currents.”

But Mr. Cunningham writes of a New York progressively alienated from its comradely, Whitmanian origins. Already in the first novella, where the boy Lucas has an encounter with Whitman himself, the city is being taken over by sinister machinery: the story concludes with a sweatshop fire, a tourde-force passage that cunningly evokes the horrifying images of September 11. By the second story, set in the present day, the city is traumatized by terrorism, on the edge of paranoia, constantly surveilled and spied on. And in Mr. Cunningham’s dystopian future, all of New York has become what Times Square is today: a simulacrum, a theme park, where tourists pay to be mock-mugged as part of the authentic Old New York experience. It is Mr. Cunningham’s knowing, worried, affectionate writing about New York, even more than his experiments with genre and narrative, that makes “Specimen Days” come to surprising life. His concern with the city and its future might be his most precious legacy from Whitman, who wrote in “Crossing Brooklyn Ferry”:

Crowds of men and women attired in the usual costumes, how curious you are to me!
On the ferry-boats the hundreds and hundreds that cross, returning home, are more curious to me than you suppose,
And you that shall cross from shore to shore years hence are more to me, and more in my meditations, than you might suppose.