People were losing their political bearings, and none of it made sense. Klein had spent a lifetime analyzing the dominant power as oligarchic: relentless, resolute, delivered from on high. She was used to connecting dots, to mapping out cause and effect in the capitalist system — from Hurricane Katrina to proliferating charter schools; from Sept. 11 to the “homeland security industry.” But it was becoming increasingly hard for her to map out what she was seeing, let alone plot it on the old left-right axis. Here was a grass-roots movement that was demanding not egalitarianism, but nativism; not solidarity, but discord. Klein was trapped inside a hall of mirrors, and she was trying to find a way out.

Before writing about her doppelgänger, Klein felt stuck. “For me, it’s very hard to disentangle writer’s block from depression,” she told me, remembering the “sense of pointlessness” she felt as the pandemic continued to grind on. “I think my crash was in the early months of the Biden administration and realizing that there was going to be an attempt to return to the same old same old.” Social media also seemed to be getting ever more poisonous. Her friend V, the playwright formerly known as Eve Ensler, recommended that Klein talk to the fiction writer Harriet Clark, who also teaches creative writing. Klein told her what she was going through: “I used to fill notebooks, you know, everywhere I went. Now I just feel unsurprised.”

Clark assigned readings, like Joan Didion’s “On Keeping a Notebook,” to encourage Klein to consider new ways of writing and noticing. At the time, Klein was arranging a move from New Jersey, where she had been teaching at Rutgers University, to British Columbia, where she had been staying since the early days of the pandemic and where her parents and brother live. Covid was still raging, and all the planning had to be done remotely. As an exercise, she wrote a personal essay about choosing what to keep and what to leave behind. Klein, who is 53, laughed as she recalled the artifacts of her former life. “Who was that person who had that many pairs of high heels and tights? Like, tights?” she joked. The germ of the book was there, she realized now, even though she hadn’t recognized it at the time. “It was about how many selves we have in our lives, and just how mutable it is.”

Compared with the single-mindedness of her previous work, in “Doppelganger,” Klein has allowed some of these selves to come through. Much of the book is funny and playful, laced with references to fiction and films, including an extended (and attentive) reading of the novel “Operation Shylock,” in which Philip Roth meets a double who calls himself Philip Roth. Some unintentional comedy comes from Wolf’s baffling tweets about “vaccines w nanopatticles that let you travel back in time” and the need to protect “general sewage supplies/waterways” from “vaccinated people’s urine/feces.”

And then there’s the rank absurdity of the Klein/Wolf mix-up. Yes, the two women are Jewish; both have brownish-blondish hair; both have written big-idea books; both have been outspoken about abuses of political power during times of crisis. But their bodies of work are distinctive, and the association between them became ever more troubling to Klein as Wolf began tweeting “pulpy theories” about 5G, about weird clouds. The confusion was widespread enough to be commemorated in a viral poem:

if the Naomi be Klein
you’re doing just fine
If the Naomi be Wolf
Oh, buddy. Ooooof.

As much as Klein recoiled at what Wolf was saying, she also felt the sting of recognition. Klein recalls the uncanny spectacle of seeing a version of her systems-level thesis in “The Shock Doctrine” — that elites will take advantage of a crisis to impose their will — twisted by the likes of Wolf, who has described Covid as “a much-hyped medical crisis” that “has taken on the role of being used as a pretext to strip us all of core freedoms.” Klein became both obsessed and repulsed, fascinated and appalled: “I felt like she had taken my ideas, fed them into a bonkers blender and then shared the thought-purée with Tucker Carlson, who nodded vehemently.” She always knew when Other Naomi had said something truly mind-boggling because her — Klein’s — Twitter mentions would fill up. (In an email, Wolf declined to comment on “Doppelganger,” explaining that she hadn’t yet read the book, but said that some of her tweets “were poorly worded and were deleted.”)