There are books that enter your life before their time; you can acknowledge their beauty and excellence, and yet walk away unchanged. This was how I first read Elizabeth Hardwick’s “Sleepless Nights,” after it was recommended in David Shields’ “Reality Hunger,” a thrilling manifesto that tries to make the case that our contemporary world is no longer well represented by realist fiction. While I loved “Sleepless Nights” on that first read — it is brilliant, brittle and strange, a book unlike any preconceived notion I had of what a novel could be — I moved on from it easily. I’ve lived two thousand and some odd days since, read hundreds of other books and published three of my own, all in a bright, hot landscape of somewhat-realist fiction.

The middle of the night has become a lonely stretch of time, especially in the past few years, with vastly increased anxiety — over climate change and politics and what lies in wait in my little sons’ future. I normally salve insomnia with reading, but few new books have felt so revolutionary or so brave as to be able to rock my tired brain to attention. Only the great ones remain: George Eliot’s infinite wisdom in “Middlemarch,” Jane Austen’s gracious and low-stakes sublimity, Dante’s “The Inferno,” which makes our world above seem downright kind. And strangely, of all the books I have reread to comfort myself, I have turned most often to Hardwick’s “Sleepless Nights,” not without a little bitter tang of irony because of its title. The book didn’t dovetail with my heart on the first reading, but the world has changed around me, and now I find myself hungering for its particularity, the steady voice of Elizabeth Hardwick a balm to my aching, vulnerable mind.

Elizabeth Hardwick grew up in Kentucky, a charming young woman with a dagger of a mind. She left for New York City after college and took up with the Partisan Review crowd, becoming best friends with Mary McCarthy and writing for The New York Review of Books from its inception. “Sleepless Nights,” her third novel, is unambiguously her chef d’oeuvre; it was published when she was 63, after a career of writing sharp, ingenious pieces of criticism and after her long marriage to (and divorce from, then reunification with) the poet Robert Lowell, whose profound psychological struggles and infidelities and plagiarism of Hardwick’s letters in his books must surely have tested her strength. As a result, “Sleepless Nights” feels elemental, an eruption of everything that had been slowly building up over decades. Though there are books that are distant kin to it — Renata Adler’s “Speedboat,” Maggie Nelson’s “Bluets” — I have read nothing close enough to be called a sibling. This is rare; a feat of originality.

“Sleepless Nights” brings the profound gift of plotlessness, as it is organized more like a piece of music than like a traditional novel, with its long slow build of themes and lives; as such, you can open it to any chapter and start to read, just as you can play movements from a symphony out of order without damaging the experience of letting individual movements pour over you. You can put the novel down at 3 a.m. and toddle off to bed, then pick it up in a different place a week later, and be carried away by its voice and description and sheer astonishing linguistic power and flexibility.