Last summer, a book changed Kohn Glay’s life.

A TikTok ad had steered him to “The Shadow Work Journal,” a slim workbook that directs readers to explore hidden parts of their unconscious — their shadow selves, in the book’s vernacular. He ordered a copy and soon was back on TikTok, fervently recommending it to his followers.

“If you’re on your spiritual journey, you absolutely need to go and get you one of these,” he says in the video, urging viewers to buy the book in the TikTok store.

The video went viral, eventually drawing more than 58 million views. Glay, who is 43 and lives in Baltimore, began holding online classes to guide people through the journal. Over the next few months, people who watched his videos bought more than 40,000 copies of the book on TikTok, and Glay earned more than $150,000 in commissions. By December, he had quit his job and now runs his own business, Happy Healin, which offers subscribers spiritual mentorship and coaching.

Glay is part of the army of TikTok influencers who helped turn “The Shadow Work Journal” into a mega bestseller. He’s so closely associated with the book that people often assume he wrote it. “It became a daily thing to tell people I’m not the author,” he said.

The real creator of “The Shadow Work Journal” is Keila Shaheen, a 25-year-old writer from Texas with a background in marketing who self-published the book in 2021 and has since been crowned “the self-help queen of TikTok.”

After the journal blew up on TikTok, Shaheen went on to sell more than 1 million copies. Most of those — nearly 700,000 copies — were sold through the TikTok shop and were marketed relentlessly by passionate influencers like Glay, who earn a 15% commission on each sale from Zenfulnote, Shaheen’s company.

Shaheen’s unusual path to bestsellerdom shows how radically book marketing and sales have been changed by TikTok. Over the past few years, publishers have frantically rushed to harness the power of the platform as viral videos and reviews by influencers have propelled sales for blockbuster authors like Colleen Hoover, Emily Henry and Sarah J. Maas.

But Shaheen is perhaps the first self-published nonfiction author to break out in a big way on the platform, a feat she accomplished by fully harnessing its potential not just for marketing but also for direct sales.

Her stunning trajectory has left many authors and publishers wondering whether that formula can be replicated and how publishers can navigate the new online retail ecosystem — a fast moving, algorithm-driven marketplace that threatens to cut them out entirely.

“To think that she achieved a million copies sold in the United States alone, without a publisher, without any international expansion, without brick-and-mortar support, it breaks all the rules of what makes a bestseller,” said Albert Lee, a literary agent with United Talent Agency, which represents Shaheen.

Others wonder just how much bigger Shaheen’s self- help empire can get. Shaheen signed a five-book deal this year with Simon & Schuster, after months of being courted by big publishing houses.

The deal includes a new, expanded edition of “The Shadow Work Journal,” which was released in late April, with a first printing of 100,000 copies, plus two new books by Shaheen.

“We really wanted to show Keila that we had a long-term vision,” said Michelle Herrera Mulligan, vice president and associate publisher of Primero Sueño Press/Atria, the Simon & Schuster imprint that signed Shaheen. “There is still a huge untapped audience for this book.”

Shaheen first encountered the idea of shadow work in 2021, when she was feeling anxious and adrift in the wake of the pandemic. She graduated from Texas A&M in 2020 with a degree in business and psychology, then found work in online retail and marketing — including a stint as a creative strategist for TikTok.

Coming out of the isolation of COVID-19, Shaheen felt disconnected and found working in a corporate environment overwhelming.

One day, while searching online for therapeutic journaling prompts, she came across references to Swiss psychoanalyst Carl Jung’s idea of the shadow self, which holds that parts of our unconscious can mask hidden fears and desires. She learned about a practice called shadow work, a somewhat fringe field that draws on Jung’s ideas to guide people as they interrogate their shadow selves, with the goal of accepting parts of themselves that make them feel guilty, ashamed or afraid.

Shaheen started posting videos on Instagram and TikTok about shadow work exercises she was trying and began getting messages from viewers asking for a printed guide. So in fall 2021, she self-published the journal and began selling copies for $19.99.

Sales were slow at first. Then, in late 2022, TikTok expanded into online retail. The platform started selling products directly through the app and created an affiliate program, which allowed influencers to post videos about products in the store and earn a commission. Once Shaheen started selling the journal through TikTok, requests came pouring in from influencers who wanted free copies in exchange for promotion.

TikTok was soon flooded with emotional videos of users filling out the journal’s pages.

The journal also drew some skepticism. Some on social media attacked shadow work as anti- Christian and even demonic. Others said it failed to live up to the hype. Still others questioned Shaheen’s credentials as a mental health guide.

Shaheen — who is described in her author biography as “a certified sound healer and behavioral therapy practitioner” — completed an online training course in cognitive- behavioral therapy but is not a licensed therapist.

Some experts in Jungian psychology worry that “The Shadow Work Journal” oversimplifies Jung’s ideas. Shaheen said she always intended the journal to be an introduction to shadow work, not a comprehensive guide.

“The journal is meant to be a bridge,” she said. “I wouldn’t say that it’s created to replace therapy.”

It’s still unclear whether “The Shadow Work Journal” will catch on with a wider demographic or if it owes its popularity to a viral trend that has waned. So far, the new edition has sold nearly 18,000 copies, according to Circana Bookscan — a healthy amount, but hardly a hit.

Herrera Mulligan, Primero Sueño’s publisher, said “The Shadow Work Journal” is just the beginning: “We really want her to be the new empress of self-help.”