During the 16th century, the English were unusually spirited in their destruction of Catholics. If you were unlucky, you might be strung up by the neck, cut down before you died, have your “privy members” hacked off, your bowels taken out and burned, your head removed, and your remainders chopped into four pieces and tossed into some ignoble hole or ditch, according to the wishes of the king or queen. You might also be rolled up into a ball by a torture machine, hung from the wrists by manacles until your body felt like it was exploding, or pinned to the ground with a sharp rock, on top of which a heavy door was mounted, on top of which other heavy things were mounted, until the weight was enough to pulverize your bones.

The punishments were so excessive that one gets the impression they were almost designed to be written about, not just seen. Even if you weren’t executed or exiled, you could be put into a prison and systematically starved until you were driven to lick the walls of your cell (to extract moisture or fungus from the stone). If you weren’t put into prison, it was likely that your cow would be taken from you. And if you didn’t own a cow, it was your sheets, your blankets, and your window-glass.

This was the kind of bleak religious climate in which John Donne—the great Metaphysical poet and clergyman, whose career straddled the reigns of Elizabeth I, James I, and Charles I—was forced to make the most difficult decision of his life. Between 1535 and 1593, at least 11 members of Donne’s family died for being Catholic—including Sir Thomas More, author of Utopia and great-uncle of Donne’s mother, Elizabeth Heywood. Donne had to ask himself: Should he be a martyr or an apostate? Embrace the faith of his family and risk a lifetime of persecution and, possibly, violent death, or join the Protestants and gamble on an eternity in Hell?

In the end, the answer was Protestantism. Not only did Donne become a Protestant; he wrote satires, screeds, and poems that sneered at Catholicism. He even became one of the most important members of the entire Anglican clergy: the dean of St. Paul’s Cathedral, a post from which he preached sermons to crowds in the hundreds and, occasionally, thousands. Some of the sermons were so stirring that he wept to the sound of his own voice.

“Exactly when Donne turned from Catholicism to Protestantism is the central boxing ring of Donne studies,” Katherine Rundell writes in her new biography, Super-Infinite: The Transformations of John Donne. It’s a question that has puzzled every biographer of Donne, including Izaak Walton, who knew him personally and wrote not only the first account of his life but what is, arguably, the first literary biography in the English language. Was it the death of his brother Henry that pushed Donne over the edge, after Henry was caught with a Catholic priest in his room and died in prison from the plague? Or, as Rundell wonders, did Donne’s conversion happen after he “licked a finger and held it to the political wind”? The change of heart could have been motivated by many things: social expediency, fear, genuine belief, rebellion, or some slurry of them all.

It’s one of the virtues of Rundell’s biography that she doesn’t dwell too long on Donne’s conversion. The thing to know about him, really, is that he was a paradox. He was obsessed with love and death, sex and sickness, beauty and ugliness, with angels and the empyrean as much as the finitude of the body. He was supposedly a flirt and “a great visitor of ladies,” but he also praised chastity and wrote of the sinfulness of flesh. He was egotistical and career-driven, self-effacing and obsequious (especially when he was trying to coax money out of his rich friends, whom he liked to butter up with verse letters). An insider and outsider, wealthy and poor, a love poet, politician, prisoner, pirate, courtier, scholar, and star preacher—he was various and ever-changing.

Donne should be a dream subject for a biography, but his archival record is rather meager. The problem isn’t a lack of written material: We have about 9,100 lines of poetry; 160 sermons, essays, and treatises on religion; meditations on illness; and 230 of his letters. But the paper trail goes quiet on his comings and goings as well as his life behind closed doors. The letters are often impersonal or formal—written with an eye to state censors—and all of his diaries and commonplace books have either disappeared or gone up in flames.

So what are the ways to shape the raw materials? R.C. Bald’s classic John Donne: A Life is impressively rigorous and thorough, but also quite boring. John Carey’s “spiritual biography,” John Donne: Life, Mind and Art, has its flashes of brilliance but is more invested in the shape of the mind and less in the externalities of the poet’s life. More recently, John Stubbs helped to flesh out the supporting characters and set the Elizabethan scene in John Donne: The Reformed Soul. What distinguishes Rundell’s new biography is how eminently readable it is. The amount of skill required to tackle such a large scholarly apparatus, tons of lifeless letters, and a story pitted with holes and then whip it into a lively, tautly plotted book about a Renaissance cleric, without forgoing any of the erudition—it’s pretty amazing.

Rundell is the author of best-selling and award-winning children’s books. She’s also a Renaissance scholar and a fellow of All Souls College, Oxford. She reportedly “begins each day with a cartwheel” and is someone who, for years, was an avid “night climber,” crawling up drain pipes and crossing the city of Oxford by roof. One imagines that this is not the typical profile of a Donne expert. That would involve a lot more tweed, a lot less trespassing, and a general inability (or unwillingness) to write playful and vivid prose.

One racy line from a Donne poem, Rundell says, contains “a pun so obvious it might as well be a little sketch of a penis.” Elizabethan necklines are described as “skat[ing] close to the nipple”; something else is compared to “a tooth in a basket of flowers”; and she says, describing Donne’s sense of humor, that he wore “his wit like a knife in his shoe.”

Rundell seems to be drawing inspiration from Donne himself, meeting her subject halfway. One of the trademarks of his style—and part of what made him “metaphysical,” according to Samuel Johnson—was that in his poetry, “the most heterogeneous ideas are yoked by violence together.” Johnson meant this as an insult, but for modernists like T.S. Eliot, this is what made Donne innovative. There is an unexpected rush and pungency to his collapsing images. Eliot explains:

When a poet’s mind is perfectly equipped for its work, it is constantly amalgamating disparate experience; the ordinary man’s experience is chaotic, irregular, fragmentary. The latter falls in love, or reads Spinoza, and these two experiences have nothing to do with each other, or with the noise of the typewriter or the smell of cooking; in the mind of the poet these experiences are always forming new wholes.

By this reasoning, Donne was basically the ur-poet of the English language. He was a master at grafting disparate things together. Women could be foxes and goats, or celestial bodies and the entire earth; love was a fish; cities had sinews; silks tended to whistle. He liked to invert expectations and to twist images past the point of sense-making. He compared his body to a map of the sky, one that physicians looked down into. He urged people to crawl into their bodies and reside there: “Be then thine own home, and in thyself dwell.” He called his arm hair his “outward Soule.”

Reading Donne makes your mind and body feel suddenly plastic, changeable. There is a poem called “The Damp” in which he imagines his own death, followed by a sort of overenthusiastic autopsy in the presence of his friends. They want to know why he died, so they have the doctor take apart his body, and by the time they get to his heart, they find a picture of his lover inside, and then—bear with me—the picture shoots a poisonous vapor of love through their bodies and murders them. Somehow, all of this takes place in one stanza that’s eight lines long.

Donne’s poetic voice was not smooth or angelic; it was knotted and difficult. “I sing not siren-like, to tempt, for I / Am harsh,” he wrote. (Alexander Pope was so disturbed by the poetic imbalance of Donne’s satires that he rewrote them to make them scan.) Unlike Donne’s contemporaries, who were faithful to the shape and sound of courtly verse, Donne was bitten by a rather ferocious death drive. He was the kind of guy who talked a lot about having stomach problems and vomiting; he almost died three times and got into the habit of comparing beds to graves. There were even moments when he relished bouts of sickness, because it meant he could be closer to dying, and thus to God: “I am so much the oftener at the gates of heaven.”

How do contemporary readers remember Donne? There is the famous line “No man is an island, entire of itself.” A good quote; hard to imagine it being put to bad use. The line comes from Devotions Upon Emergent Occasions, 23 meditations that Donne wrote on what he thought was his deathbed. (There’s another line further down in the paragraph that’s also famous, though only because Hemingway used it for the title of his novel For Whom the Bell Tolls.)

Then we have the poems—in particular, the ones about sex and death. “The Flea,” his most popular, is about a man who’s trying to get laid. His logic is that because the flea bit him and then bit his beloved, it means that their blood is already combined inside of the flea. (“Me it sucked first, and now sucks thee / And in this flea, our two bloods mingled be.”) Therefore, they might as well have sex.

Donne is also known for the drama and tragedy of his relationship to Anne More. She was the daughter of Donne’s onetime employer, the powerful Sir Thomas Egerton, and after they eloped, Donne was thrown into prison. For some reason, the pun he wrote afterward is famous: “John Donne, Anne Donne, Undone.” (He liked to riff on her name in his poems.) They lived in poverty for years and lost five of their 12 children before Anne herself died at the age of 33.

If these are the ways that people remember Donne today, there’s nothing particularly egregious about that. (Even if the island quote and the erotic poems represent a rather tiny, unrepresentative slice of his work.) But one thing I was hoping for, from Rundell’s book, was that it would elaborate on Donne’s legacy. Any story of Donne’s life is also a story about his afterlife, about how swaths of 20th-century literature and literary criticism remade itself in his image. It’s not just the standard reception narrative—a writer’s stock rising and falling with the decades—but a rather unusual feat of rebirth.

When T.S. Eliot reshuffled the canon with his famous essay “The Metaphysical Poets”—slyly elevating them over Milton—he turned Donne into one of the major precursors of modernism. W.H. Auden, Hart Crane, Djuna Barnes—they were all serious readers of Donne. And his work continued to attract devotees throughout the century. There was William Empson and Cleanth Brooks. (Brooks’s seminal text of the New Criticism, The Well Wrought Urn, takes its title from Donne; and Empson wrote some great, bizarre essays about him, such as “Donne the Space Man,” in which he argues that Donne wanted to be an astronaut.) Elizabeth Hardwick went to grad school at Columbia in 1940 to write a thesis on the Metaphysical poets. And William Gass said it was Donne’s prose we should look to, along with that of the other Elizabethan and Jacobean stylists who elevated essays into art.

According to the Oxford English Dictionary, Donne is responsible for the first use of approximately 340 words in our language, including “emancipation,” “bystander,” and “jig.” (Some of the others, like “imbrothelled,” are not as useful.) And today, writers and poets are still going back to him. Just recently, Brian Dillon wrote an exceptional short essay about Donne, a study of a single sentence from “Death’s Duel”—the funeral sermon that he effectively gave for himself right before he died. Here is the sentence:

Wee have a winding sheete in our Mothers wombe, which growes with us from our conception, and wee come into the world, wound up in that winding sheet, for wee come to seeke a grave; And as prisoners discharg’d of actions may lye for fees; so when the wombe hath discharg’d us, yet we are bound to it by cordes of flesh, by such a string as that wee cannot goe thence, nor stay there.

It’s a weird sentence. Not only because it gives up on Ciceronian ideas of prose, the preference for balance and poise, in favor of something much shaggier, more winding. But also because of its “grotesque chain of associations,” Dillon writes, whereby “the caul or amniotic membrane is itself a shroud, and the umbilical cord a chain by which at birth we are imprisoned.” It leaves us stranded between birth and death and gets tangled in its own logic. You can read the sentence a dozen times and never get closer to reverse-engineering it.

One wonders where else Donne has leaked into our culture and language. But, admittedly, that’s not the scope of Rundell’s biography. Her business is piecing together a portrait of that strange, mercurial man, “the greatest writer of desire in the English language.” Even though he was remarkable on the subjects of love and sex, and their analogues in illness and death, what Rundell helps us to appreciate is his joy and wit. There’s something about him that always seems to be smiling. “His poetry explicitly about death is rarely sad: it thrums with strange images of living,” Rundell writes. Even on his sickbed, Donne imagined his thoughts reaching out toward the world, becoming the world, overrunning the sun “in one pace, one step, everywhere.”