The opening sentence of Emily Witt’s Future Sex—“I was single, straight, and female”—might, in a different sort of book, set the reader up for the narrator’s quest to transcend the first element of that self-identification. The condition of singleness, after all, is traditionally understood as a sort of existential antechamber to the Valhalla of marriage, or of otherwise “settling down.” Early in life, the single person is thought of as not yet settled down; as he or she ages, this becomes seen as a failure to do so.

In the early pages of her book, Witt writes of turning 30, and of conceiving of her singleness as an interim state; she describes a condition of objectless longing, a special form of loneliness that can only be generated by the technologies of connection. “I stared at rippling ellipses on screens,” she writes. “I forensically analyzed social media photographs. I expressed levity with exclamation points, spelled-out laughs, and emoticons. I artificially delayed my responses. There was a great posturing of busyness, of not having noticed your text until just now.” Her friends express a quasi-mystical belief that she will indeed find love, or be found by it, and cease to be a soul “flitting through limbo [...] awaiting the brass trumpets and wedding bells of the eschaton.”

There’s probably no need for a spoiler alert in my telling you that the pages of Future Sex at no point resound with any such trumpets or bells. Despite her irresistible title, Witt isn’t primarily interested in the future—either her own, or that of sex and relationships in general. Which is not to suggest that she isn’t anxiously curious about these matters, but rather that her book is an attempt to encounter singleness on its own terms, as a mode of being in the world—or the world, at any rate, as it’s presently experienced by more or less young, more or less privileged, and more or less straight Americans.

Although the book is framed by its author’s own experience, it wouldn’t be accurate to describe it as a memoir. The action—and it contains, let me assure you, a great abundance and diversity of action—begins in earnest with Witt leaving New York and striking out West for San Francisco, there to seek her sexual fortune. She begins internet dating, but seems unable to work up the enthusiasm, with any of these algorithmically selected potential mates, for the kind of casual sex that flows naturally enough from going to parties and meeting men IRL. There are more rippling ellipses, more unanswered messages. Witt delicately and skillfully summons the muted mournfulness of these failures to connect, the doubled alienation of technologically mediated distance. OkCupid delivers her a sensitive composer with whom she shares an interest in the poetry of Wallace Stevens and the fiction of Thomas Pynchon, but the encounter fails to develop into anything exciting, and she eventually stops responding to his increasingly plaintive messages. “In the months that followed,” she writes, “he continued to write, long e-mails with updates of his life, and I continued not responding until it came to seem as if he were lobbing his sadness into a black hole, where I absorbed it into my own sadness.”

Witt’s desire to get beyond this stasis, her curiosity about what it is she really wants, opens out onto a vista of sexual otherness, and an episodic series of journalistic engagements with that otherness. As such, the book is largely comprised of a sequence of more-or-less-standalone essays reporting from various points on the Bay Area sexual panorama. There’s a chapter in which she attends meetings organized by a San Francisco–based group called OneTaste, an apparently thriving business dedicated to the practice and promotion of something called Orgasmic Meditation. This involves a ritual whereby a woman lies down pantsless next to her partner, who must first describe the woman’s vulva in poetic detail and then, wearing a pair of heavily lubricated latex gloves, slowly and gently manipulate the clitoris for precisely 15 minutes before stopping, orgasm or no orgasm, at the behest of an iPhone stopwatch. The whole setup seems weirdly, almost creepily, de-eroticized, and Witt navigates her ambivalence about it with fascinating honesty and deftness. The piece culminates, perhaps inevitably, with her own experience with the practice, under the detached ministrations of one of the organization’s blandly handsome personnel. The episode is literally anti-climactic, and is exemplary of the combination of irony and pathos that makes the book such an astringent pleasure to read:

I felt no desire to have sex with the man holding my legs, but feeling his breath rise and fall against my leg brought a feeling of deep, intense comfort. I was not transported by rapture. This was quiet and still. I concentrated on breathing and feeling the pressure of his body. At one point he said, thoughtfully, “I feel a deep swelling at the base of my cock.” Then the bell on his iPhone chimed and it was over.

Although she is often at the periphery of the action, Witt is mostly central as a nonfiction observer-narrator figure. Even at its funniest (and it’s frequently very funny) there is a curiosity and an openness to her writing that prevents the laughs ever feeling as though they are imposed by force from above. She attends a porno shoot—a hardcore sadomasochistic deal, filmed in front of a crowd, involving the binding and scrupulously staged humiliation of a young woman—and reveals a strange, awkward humanity at work in what might easily be portrayed as a crowd of baying misogynist weirdos. (“ ‘You are beautiful and I’d take you to meet my mother!’ yelled one man who had been particularly enthusiastic about yelling ‘worthless cunt.’ ... The crowd was drunk and excited, although not entirely unembarrassed. ‘Make that bitch choke,’ shouted the shouty man. Then: ‘Sorry!’ ”)

The book’s longest section concerns a group of San Francisco polyamorists, but—like the book as a whole—it just as crucially concerns the culture of boundless optimism and self-enclosed privilege around Bay Area techies. Some of the book’s best writing sees Witt firing on all essayistic cylinders on the peculiarity, and pervasiveness, of this culture:

They were adults, but they could seem like children, because they were so positive, because they liked to play, because they were marketed to with bright colors, clean, day-lit spaces, and nutritious snacks, and because their success was in part attributed to the fact that they had arrived in early adulthood and apparently had never broken any rules. Their sex lives were impossible to fathom, because they seemed never to have lived in darkness. They had grown up observing foreign wars, economic inequality, and ecological catastrophe, crises that they earnestly discussed on their digital feeds but avoided internalizing as despair.

Part of what makes Future Sex so compelling, and so fascinating, is the indeterminacy of its author’s own position in relation to the world she’s writing about. She’s usually more than just an observer, but she’s also rarely an insider. (She alludes to this ambivalence from time to time, describing herself at one point as “just a visitor, or rather neither here nor there, someone undertaking an abstract inquiry but not yet with true intention.”) She’s a little older than this particular group of free-loving techies, but in writing about the people around her, she’s as often as not also writing about herself.

The book is at its most conventional, and least interesting, during a handful of longish stretches—most notably in that exploration of the polyamorist scene—in which she straightforwardly narrates stories in which she herself has no real personal involvement. There is a subtle drop-off in style and energy in these parts, a kind of journalistic dutifulness which creeps into the writing, and reading them I found myself impatient for Witt to reassert herself as an embodied presence in the book.

The book’s highpoint comes near the end, in the form of a personal essay about attending Burning Man with a bunch of well-heeled Silicon Valley types—on the face of it, about as unappealing a prospect for a piece of writing as it’s possible to imagine. Not all that much happens: She travels there with a guy she previously hooked up with at a wedding in Portugal; she cycles around; she gets high; she meets a charming anarchist at a pop-up library and they bond over Ursula K. LeGuin and Claude Levi-Strauss; they take a naked steam bath together and eventually have sex (an event which is passed over in decorous silence). But the piece, a version of which previously appeared in the London Review of Books, is filled with superb observations, and distinguished by Witt’s characteristic combination of openness and skepticism. Her own experience of the festival is positive and expansive, but she is far from wide-eyed about the utopian pretensions of the techies who have made Black Rock City a holiday outpost of Mountain View, a kind of TEDx Ibiza:

The hypocrisy of the “creative autonomous zone” weighed on me. Many of these people would go back to their lives and back to work on the great farces of our age. They wouldn’t argue for the decriminalization of the drugs they had used; they wouldn’t want anyone to know about their time in the orgy dome. That they had cheered at the funeral pyre of a Facebook “like” wouldn’t play well on Tuesday in the cafeteria at Facebook.

Witt could be seen as focusing too restrictedly, in these essays, on the experience of a particular social world: The book is peopled overwhelmingly by upper-middle-class heterosexuals. But her own centrality to the stories she is telling, the fact that they all work outward from her inner life, largely exonerates this sociological narrowness. And this personal grounding is, in the end, the book’s greatest strength; it’s Witt’s distinctive presence as an observer and protagonist, in other words, her simultaneous openness and ironic detachment, that makes Future Sex such an engrossing and illuminating experience. By the end of the book, neither Witt’s own future nor that of sex itself seem any closer to being known. (“The future was a discomfiting cultural story,” as she puts it, “and difficult to discern.”) But the present seems nearer, and stranger, and more intimately known.

Read the rest of the pieces in the Slate Book Review.