In a black leather notebook — or its iPhone equivalent, the Notes app — Dessa jots down an idea in one of three piles: Song. Poetry. Essay.

Dessa does them all.

A satisfying sonic pattern lands in song. A well-drawn image might get filed under poetry. An idea about the state of political rhetoric? “That’s going to ask for some real ink,” Dessa said. “That’s going to ask for 5,000 words — which would make for an insufferably long song.”

Dessa started in slam poetry, made her name rapping with the Doomtree crew. Now, her essay writing is getting its due. The New York Times recently published her evocative travel tales from London and New Orleans and, this week, New York publisher Dutton Books will release her debut memoir, “My Own Devices: True Stories From the Road on Music, Science and Senseless Love.”

Dessa, 37, writes like she raps like she talks — with a sharp vocabulary, an eye for telling detail and a tightrope intensity.

“I started rapping seriously, if inexpertly, at about the same time I fell in love (also seriously and inexpertly),” Dessa begins the book. “I did both with the owner of a Ford Festiva.”

Publishing essays has made her “happier as a musician because I wasn’t asking a rap song to be an essay anymore,” Dessa said, twisting one of the many silver rings stacked on her long fingers. “In some ways I had been looking to music to satisfy every aesthetic ambition and desire.”

Dessa hums with aesthetic ambition. She splits her time between Minneapolis and Manhattan now. During a recent stop here, she met with the Minnesota Orchestra about a show and a seamstress about a dress, rehearsed and performed with Doomtree, did a pair of TV and radio interviews and bought her mom a belated birthday meal. Given 90 seconds between two tasks, she’ll fill it with a third. “I have tweets loaded up where, if you were to go to the bathroom, I know which ones I’ll send.”

In fact, a young Margret Wander, high school valedictorian and college philosophy major, had wanted to be a writer, not a rapper. For years, she submitted essays to literary magazines. Then a friend encouraged her to perform an essay at a slam poetry contest. She slayed.

“So it was an inability to get published that was, in part, what pushed me to the stage,” Dessa said.

In the new book’s first essay, she describes learning to rap with her bandmate and boyfriend P.O.S., aka Stef Alexander, “idling in the parking lot of an Old Country Buffet,” as he pounded a beat on his Festiva’s roof. Her verses, then, were light. But P.O.S. had read her essays, which were different: “They had extended metaphors, literary allusions, subtext. It had never occurred to me to try to rap like that.”

Rendering him fully in the book without naming him — she dubs him, simply, X — Dessa tells their love story and, perhaps more important, their falling-out-of-love story. It’s specific, aching. She tells how he nicknamed her long toes “tingers,” admitting how it hurt to look at them: “I find myself in the dumb and embarrassing position in which my own feet make me sad.”

The first draft had less of that. She had been a bit guarded, cerebral. But an editor convinced her to open up.

“I wanted to be sure I didn’t cross the line between frank, candid and vulnerable into maudlin, confessional, sentimental,” she said. “Because there is that trend, right? Here’s my feelings and they’re precious. My feelings are not precious.

“It’s only good writing and craft and storytelling that would make that experience interesting to anybody but me and maybe my mother.”

Throughout, Dessa steps back, using scientific case studies as metaphors to examine herself, her family and her relationships. Then she describes becoming a case study herself. After 14 years of starts and stops and parking lot tears, she turned to neurofeedback and fMRI technology to excise her love for P.O.S. from her brain. (Yes, she reassures friends and readers, she’s seen “Eternal Sunshine of the Spotless Mind.”)

She sat, electrodes stuck to her scalp, as the “pleasant chiming started, like a malleted run up a vibraphone.”

That process — part art project, part effort to get better — rings on her new album, too, titled “Chime.” The project also provided the backbone for two sold-out shows at Orchestra Hall last spring, a stage she’ll return to Oct. 5-6.

Dessa’s deepest lyrics have long drawn from heartache. But she’s careful to temper heartache with the technical, she said. That’s partly because as the only woman in her hip-hop crew, she knows well the double standard.

“If a female voice expresses, let’s say, feelings of loss and abandonment, one might find that more listeners respond, thinking, ‘Well, you would,’ ” she said. “Whereas when a dude does it, it’s like, ‘Shut up, Jeff has something to say.’ ” She threw her arm across the coffee shop table, silencing the invisible crowd and raising an eyebrow.

“We imagine we’re being let in on a very special vulnerable part of a male performer,” when he talks about love, she said, “whereas we just anticipate this constant stream of emotional drivel from a female performer.”

In the book, Dessa describes moving to New York City as a needed break from P.O.S. But it’s a career move, too. Dessa is, by her own account, “already old for a rapper.” (Even as a kid, she said, her mom described her as 8 years old going on 40: “That kind of midlife anxiety seems to be part of my makeup.”) She knows her numbers, “the arcade game” of albums sold, tracks played and rooms filled.

“But my goals aren’t formulated in terms of those numbers,” she said. “I would like to participate in not just money-making but culture-making,” reaching across geography and genre.

Since Doomtree’s early days, “playing to 30 people in Phoenix,” it was clear that for Dessa, music was “only part of the puzzle,” said Aaron “Lazerbeak” Mader, Doomtree beatmaker and boss. The crew always pushed its members’ art and, in Dessa’s case, that meant “OK, well, now we’re a printing press,” he said. (Doomtree released Dessa’s first chapbook, “Spiral Bound,” in 2009.)

Mader could imagine Dessa going further. Politics, maybe. Acting.

“Anything I say would almost do it a disservice,” he said. “She’s proven to me that anything she’s going to set her mind to, she’s going to do — and do it awesome.”