Dreams are boring. On the list of tedious conversation topics, they fall somewhere between the five-day forecast and golf. As for writing about them, even Henry James, who’s seldom accused of playing to the cheap seats, had a rule: “Tell a dream, lose a reader.” I can remember when I accepted that my own unconscious was not a fount of fascination—I’d dreamed, at length and in detail, of owning an iPhone that charged really, really fast.

How unfair it is, then, that Vladimir Nabokov can show up, decades after his death, with a store of dreams more lush and enthralling than many waking lives. In 1964, living in opulence at Switzerland’s Montreux Palace Hotel, Nabokov began to keep a dream diary of a sort, dutifully inscribing his memories on index cards at his bedside in rubber-banded stacks. These cards, and Nabokov’s efforts to parse them, are the foundation of “Insomniac Dreams,” a recently published chronicle of the author’s oneiric experiments, edited by Gennady Barabtarlo, a professor at the University of Missouri.

Nabokov’s ambitions weren’t interpretive. He “held nothing but contempt for Freud’s crude oneirology,” Barabtarlo explains, and in tracking his dreams he wasn’t turning his gaze inward. For him, the mystery was outside—far outside. Nabokov had been reading deeply into serialism, a philosophy positing that time is reversible. The theory came from J. W. Dunne, a British engineer and armchair philosopher who, in 1927, published “An Experiment with Time,” arguing, in part, that our dreams afforded us rare access to a higher order of time. Was it possible that we were glimpsing snatches of the future in our dreams—that what we wrote off as déjà vu was actually a leap into the metaphysical ether? Dunne himself claimed to have had no fewer than eight precognitive dreams, including one in which he foresaw a headline about a volcanic eruption.

If all of this sounds too batty for a man of faculties, consider that Dunne’s “An Experiment with Time” had gained currency among a number of other writers, including James Joyce, T. S. Eliot, and Aldous Huxley. Its path to Nabokov is unclear, but, however it came to him, in its pages he recognized a fellow-traveller. (The author had his mystical side, Barabtarlo notes, “and the notion of metaphysical interfusion with, even intervention into, one’s life was very close to him.”) Consider, too, that, by 1964, when he began keeping his dream diary, Nabokov was barely sleeping at all. At sixty-five, he had an enlarged prostate that exacerbated his lifelong insomnia. He described episodes of “hopelessness and nervous urination,” his sleep punctured as often as nine times a night by “toilet interruptions.” In extremis, he turned to powerful sedatives and hypnotics, but even with these he struggled to make it through the night. In the depths of sleeplessness, mired in a somnolent fog, who among us wouldn’t feel a little oracular?

To detect precognition, Dunne laid out an exacting regimen for recording one’s dreams. Nabokov decided to follow it scrupulously, and almost instantly he found himself brimming with precognitive powers. On the second night, he dreamed of a clock set at half past ten; the next day, he came across the very same time in Dunne’s book. That’s nice, but it’s not volcanic-eruption nice. A few nights later, he saw a more “incontestable success” while dreaming about a museum: “I was absent-mindedly eating exhibits on the table—bricks of crumbly stuff which I had apparently taken for some kind of dusty insipid pastry but which were actually samples of rare soils.” Afterward, watching French television, he came across a program discussing soil samples in Senegal. Eureka! He had eaten the dirt of a future time.

And yet Nabokov didn’t seem to linger on his victory or its metaphysical ramifications. Though he kept up his index-card routine for eighty nights, he drifted from Dunne’s method. Rather than flagging his dreams for their precognitive potential, he began to find patterns among them, breaking them into categories: nostalgic or erotic, shaped by current events or professional anxieties. Apart from a dry spell he referred to as “dream constipation,” Nabokov was a prodigious dreamer, his mind a wellspring of trenchant, tender, and perturbing images that he recounts with verve. An old Cambridge classmate “gloomily consumes a thick red steak, holding it rather daintily, the nails of his long fingers glisten[ing] with cherry-red varnish.” A cryptic caller “wonders how I knew she was Russian. I answer dream-logically that only Russian women speak so loud on the phone.” There are capers: in one, Nabokov and his son, Dmitri, “are trying to track down a repulsive plump little boy who has killed another child—perhaps his sister.” And there are intimations of mortality: “A tremendous very black larch paradoxically posing as a Christmas tree completely stripped of its toys, tinsel, and lights, appeared in its abstract starkness as the emblem of permanent dissolution.”

There are also butterflies. Nabokov was a skillful lepidopterist, and he’d taken up residence in Montreux in part because it sat at the foot of the Alps, where rare species fluttered. He had a recurring nightmare of “finding myself in the haunts of interesting butterflies without my butterfly net and being reduced to capturing and messing up a rarity with my fingers.” In an ominous instance, a butterfly “eyes me in conscious agony as I try to kill it by pinching its thick thorax—very tenacious of life. Finally slip it into a Morocco case—old, red, zippered.” On another night, Nabokov lashes into a stranger with the “light metal, vulcanized handle” of his butterfly net. The stranger lives.

Barabtarlo claims that “a good Freudian” of his acquaintance found a “dearth of material suitable for standard psycho-interpretation” in these dreams. And there is something enchantingly agnostic about them. Full of slippage and vague yearnings, they feel like the scaffolding around a vast emotional labyrinth, never more so than in moments of fleeting intimacy. “Find some fruit in vase on side board,” Nabokov writes. “Take a banana after making sure there is one left for [Dmitri].” Seeing his mother off at a cable car, he frets, “I have not kissed her goodbye and this bothers me.” More disturbingly, with his wife, Véra, an episode of envy explodes into violence:

Dancing with Vé. Her open dress, oddly speckled and summery. A man kisses her in passing. I clutch him by the head and bang his face with such vicious force against the wall that he almost gets meat-hooked, on some fixtures on the wall . . . Detaches himself with face all bloody and stumbles away.

If Nabokov drew any conclusions from the experiment, he was careful to keep them broad. In 1969, he published “Ada,” the novel that brought to bear much of his thinking on dreams and time. (Helpfully, Barabtarlo includes extracts from it, and from Nabokov’s corpus, in “Insomniac Dreams,” animating the connection between the writer and the dreamer.) At one point, Van Veen, the novel’s nonagenarian narrator, declaims: “What are dreams? A random sequence of scenes, trivial or tragic, viatic or static, fantastic or familiar, featuring more or less plausible events patched up with grotesque details, and recasting dead people in new settings.” True enough, but this ignores the sorcery running through them—the tendrils of magic that led Nabokov to believe in prophecies. Veen is closer to the mark when he speaks of dreams as “tricks of an agent of Chronos,” suggesting that “some law of logic should fix the number of coincidences, in a given domain, after which they cease to be coincidences, and form, instead, the living organism of a new truth.”

The germ of that new truth is in “Insomniac Dreams,” which is, above all, a meditation on the ways our dreams unmoor us—from ourselves, from one another, from the most basic sense of duration. Barabtarlo points out that time in fiction, like time in dreams, has qualities of “passing, jumping, bucking, crawling, elapsing, warping, forking, reversing that we experience but can never quite get accustomed to in the course of life.” Nabokov had mastered those effects, perhaps because he was willing to accept that the river of time was more like a salt lake, rapidly evaporating. Or maybe it wasn’t even that. “The solution of the supreme mystery,” he once dreamed, “is that the cosmos with all its galaxies is a blue drop in the hollow of my palm (thus deprived of all the terrors of infinity). Simple.”