"THINK HOW you feel when a friend is telling you how happy she is; are you always happy for her? I doubt it!" says the writer Maggie Nelson via email. We're discussing her latest book, The Argonauts, recently published by Graywolf Press, which takes as its subject something comparatively rare: happiness.

"I was very inspired by [Michael] Snediker's work Queer Optimism here, specifically this line of thought: 'I'm riveted by the idea that joy could be a guarantor of truth—differently put, that joy could be persuasive.... What if happiness could outlast fleeting moments, without that persistence attenuating the quality of happiness? What if, instead of attenuating happiness, this extension of happiness opened it up to critical investigations that didn't (a priori) doubt it, but instead made happiness complicated, and strange?' I wrote The Argonauts in partial response to this call."

When Nelson says that writing about happiness was a challenge, don't think she's being modest—it probably would have been comparatively easier for her to go dark. She's built a career out of writing about violence and heartbreak in some form, from 2011's investigation into The Art of Cruelty, to a mixed-genre memoir addressing the impact of a murder on her family (2005's Jane: A Murder) and 2009's Bluets, a poetry-adjacent book I recommend to anyone who thinks they hate poetry, which charts the convergence of the color blue with all manner of loss. It may seem perverse to say that a book centered on a murder or a debilitating heartbreak is beautiful, that it carries real emotional weight; but in Nelson's case, it is, and it does. She's a poet and a critic who cuts close to the bone with her writing; no one is safe from her intellectual scrutiny, least of all herself.

It won't surprise any Nelson fans to hear that she brings this same rigor to The Argonauts. Yes, it is a love story. No, it's not like any love story you've ever read. It's as much an account of queer family-building and shifting identities as romance, centering on Nelson's marriage to the artist Harry Dodge, as Nelson navigates motherhood for the first time, and Harry, who is gender-fluid, undergoes sex reassignment surgery. It's also a book deeply interested in the possibility of love and happiness not as fleeting conditions, but continuous threads.

Nelson's title alludes to Roland Barthes' comparison of a person who says "I love you" to "the Argonaut renewing his ship during its voyage without changing its name." It's an image Nelson touches on again and again, as she considers the difficulties of maintaining a happy, close-knit family life, juxtaposing her own story with textual references covering everything from Eve Kosofsky Sedgwick's Touching Feeling to André Breton's Mad Love. But The Argonauts is neither a dry academic text, nor a traditional narrative memoir. Instead, Nelson writes in disconnected paragraphs, letting ideas of queer theory bleed into practice in her own life (or not, as the case may be).

"Sentences are not emotional but paragraphs are," Gertrude Stein once wrote, and this holds true for a book like The Argonauts. In letting us into these fragmented flashes of life, then glimpses into research, we are invited into close communion with Nelson's experience. It's an approach that feels generous and intimate, which is perhaps how Nelson gets away with writing about how happy she is without ever seeming alienating or glib. There's also a sense that her happiness is hard-won. "I feel I can give you everything without giving myself away," she says to Harry at one point. "If one does one's solitude right, this is the prize."

Go to any Maggie Nelson reading, and afterward, a cavalcade of young, bookish-looking women carrying copies of Bluets will mob her. Having been one of those women, I can tell you that they're there because they have all at one point sought identification in Nelson's account of heartbreak; of all of Nelson's books, Bluets has a cult-classic status, and for good reason. But when I think back to Nelson's question about her new book, about your hypothetical friend who is happy—are you happy for her?—the answer, in this case, surprises me. I am. If Bluets is the kind of book that breaks itself open, that makes you realize your sadness is not particularly fascinating after all, but universal, then The Argonauts is the kind of book that reminds you that sadness is temporary, but that given the right conditions, happiness could, perhaps, be infinite.