The apparent subject of the poem is familiar: the romantic fascination that older men have for younger women — a favorite of poets for centuries. Seidel’s take on such couplings — “It’s almost incest when it gets to this” — is as novel as it is harsh, even if the line’s iambic pentameter is sweet. So much of your susceptibility to Seidel’s poetry depends upon how you receive — or are repelled by — such loaded lines. And “incest” isn’t even the half of it, only the base camp from which “Climbing Everest” begins its priapic ascent to an even more perilous view. For the title, we come to understand, is a metaphor for the sexual act the poem goes on to detail, in which an old man makes the deliriously pleasurable but nonetheless arduous and by all rights deadly trip into seductively thin, late-life sexual air. When the poet reaches that summit, he pays the price, reduced to being “constantly out of breath . . . reporting to the world from an oxygen tent.” The poet’s mind makes its weary march to the exit music of the poem’s final lines:

A naked woman my age is just a total nightmare,

But right now one is coming through the door

With a mop, to mop up the cow ﬂops on the floor.

She kisses the train wreck in the tent and combs his white hair.

“Those lines caused a great ruckus,” Seidel told me during dinner, ruefully. “I got lots of extraordinarily unpleasant mail.” At first, it would seem easy to understand why. In a poem that features an old man having sex with a very young woman, so frank a statement as “A naked woman my age is just a total nightmare” could seem uncomplicatedly cruel, could seem merely cruel. And yet, aging is a nightmare, totally so, a nightmare from which each of us — when we become, inevitably, “the train wreck” the poet has by poem’s end — would only too gladly awake. Seen in this light, Seidel’s line, and the larger poem it serves, presents, with utter candor, the nightmarishness of bodily descent and responds, with honest disgust, to the indignity of that decline. As may be said of so many of Seidel’s poems, “Climbing Everest” produces not relief from experience nor reassurance about experience but — in all its complexity — experience itself.

“When he mentions East Hampton or the Carlyle or Le Cirque or Ducati,” the former poet laureate Billy Collins told me, “it doesn’t even seem like name-dropping. He does what every exciting poet must do: avoid writing what everyone thinks of as ‘poetry.’ ” Collins’s quotation marks around “poetry” are the keys that begin to unlock Seidel’s art. As Lorin Stein, an editor at Seidel’s publishing house, Farrar, Straus & Giroux, and a friend of Seidel’s, explained recently, Seidel’s qualities as a poet are in direct opposition to the poetry of many of his peers. “A lot of ways that people gin themselves up to write poetry nowadays require a setting aside of certain crass realities,” Stein said. “Crass realities of everyday colloquial communication; crass realities of money and power and sex; crass realities of the ‘I’ in its filthier manifestations. A lot of contemporary poetry has manufactured these great machines for avoiding coarseness — the dream of an escape.” That Seidel’s poems embrace the crassness at the heart of modern living makes him sound a good deal more like a novelist in the 19th-century mode — Stendhal and his mirror walking down the street reflecting modern life.

And novelists are among Seidel’s most articulate advocates. Norman Rush recognizes how Seidel’s choices can be misunderstood: “The risks Seidel takes have to do with threatening the potential affection of new readers. They may see him as a ‘swell’ and take that presentation as reason enough not to be interested in what he’s doing. He doesn’t cozen the reader. But if you persist, the power and profundity of Seidel’s games, and his nerve, will get you — draw you into the extremely complex set of experiences that he’s laid out for you to have.”

“I GREW UP,” SEIDEL TOLD ME one weirdly warm December afternoon at a diner on upper Broadway near where he lives, “with very large beautifully dark blue trucks with very chaste excellent elegant white lettering saying seidel everywhere you went.” This was in what Seidel describes as the “fierce cold” and “hothouse green sweetness” of the St. Louis of his birth, in 1936. The trucks of the flourishing family business distributed coal and, in summer, ice to white and black families and businesses in the segregated city. Seidel’s father and uncle ran the business started by their father, Seidel’s grandfather, a Russian-Jewish émigré. The Seidels lived well. There were maids, a cook. In that privileged atmosphere, Seidel did not want but, very early, came to know what he wanted — and didn’t.

“I was thought by my cranky violin teacher” — a first violinist of the St. Louis Symphony Orchestra — “to be the future, his future.” But when Seidel was 11, he abandoned the instrument in disgust. “I arrived for my lesson and found seated there a kid named John Perkins, a little older than me and well known in St. Louis as an enormously gifted composer and piano player — a genius. My teacher had asked Perkins to come round without having asked me if it were appropriate. And I was just enraged, to the point of tears. I remember the magnification of a tear on my violin, the grain on the fiddle enlarged as I looked down at it. And of course what was appalling about finding Perkins there was also heartbreaking because what he was doing was showing me off.” This was not the last occasion when Seidel would bridle at not having a hand in how he was presented to the world. ‘’When I was asked if I wanted to be Bar Mitzvahed, I was promised that if I did it, two things would come my way,” Seidel explained. “One, I would learn Hebrew — that turned out not to be true — and two, that the speech of the coming of age that I would give I would be able to write and deliver, all on my own. That also turned out to be untrue. There was an enormous and seriously unpleasant struggle between me and the rabbi, in my considerable bitterness and disappointment over learning that the guy wanted me to deliver a speech of nothingness. So I refused. Everybody having been invited, I said I was terribly sorry, I wasn’t going through with it. In the end I gave in. I gave some meaningless speech — part his, part mine. And that was it for religion.”

In the autumn before his Bar Mitzvah, the 12-year-old made a discovery. In the Oct. 25, 1948, issue of Time, Seidel saw a review of Ezra Pound’s long poem “The Cantos.” The unsigned article offers little enduring interest as journalism but provided Seidel with his first exposure to Pound’s verse, lines of which the review quoted, including some from “The Pisan Cantos,” written while Pound was detained in Italy by the U.S. Army during World War II:

What thou lovest well remains,

the rest is dross

What thou lov’st well shall not be reft from thee

What thou lov’st well is thy true heritage