By ALEXANDRA ALTER
“I can’t stay in the lines,” she said sheepishly.
Not that it matters. Ms. Basford’s coloring book “Secret Garden,” a 96-page collection of elaborate black-and-white ink drawings of flowers, leaves, trees and birds, has become a global best-seller.
Since its release in spring 2013, “Secret Garden” has sold more than 1.4 million copies in 22 languages. It shot to the top of Amazon’s best-seller list this month, overtaking books by authors like Harper Lee, Anthony Doerr and Paula Hawkins. Her follow-up, “Enchanted Forest,” which came out in February, is briskly selling through its first print run of nearly 226,000 copies.
What makes Ms. Basford’s breakout success all the more surprising is her target audience: adults who like coloring books.
There are, it seems, a lot of them. Though it is tempting to describe the market for her books as niche, Ms. Basford, a 31-year-old illustrator in Aberdeenshire, Scotland, has quickly outgrown that label.
Like Play-Doh, jungle gyms and nursery rhymes, coloring books have always seemed best suited for the preschool set. So Ms. Basford and her publisher were surprised to learn that there was a robust — and lucrative — market for coloring books aimed at grown-ups. When they first tested the waters with “Secret Garden” a year ago, they released a cautiously optimistic first printing of 16,000 books.
“I thought my mom was going to have to buy a lot of copies,” Ms. Basford said. “When the sales started to take off, it was a real shock.”
Surging demand caught Ms. Basford and her publisher off guard. Fan mail poured in from busy professionals and parents who confided to Ms. Basford that they found coloring in her books relaxing. More accolades flowed on social media, as people posted images from their coloring books.
Hard-core fans often buy several copies of her books at a time, to experiment with different color combinations. Others have turned it into a social activity. Rebekah Jean Duthie, who lives in Queensland, Australia, and works for the Australian Red Cross, says she regularly gathers with friends for “coloring circles” at cafes and in one another’s homes.
“Each page can transport you back to a gentler time of life,” she said of Ms. Basford’s books in an email.
Ms. Basford has become something of a literary celebrity in South Korea, where “Secret Garden” has sold more than 430,000 copies, she says. The craze was kicked off in part, it seems, by a Korean pop star, Kim Ki-bum, who posted a delicately colored-in floral pattern from Ms. Basford’s book on Instagram, where he has 1.8 million followers.
Part of the apparent appeal is the tactile, interactive nature of the books, which offer respite to the screen-weary. “People are really excited to do something analog and creative, at a time when we’re all so overwhelmed by screens and the Internet,” she said. “And coloring is not as scary as a blank sheet of paper or canvas. It’s a great way to de-stress.”
Ms. Basford started out in fashion, working on silk-screen designs. Then she opened a studio on her parents’ trout and salmon farm in Scotland, and began designing hand-drawn wallpaper for luxury hotels and boutiques. When the financial crisis hit, her business evaporated. She closed the studio and found work as a commercial illustrator for companies like Starbucks, Nike and Sony.
Her publishing break came in 2011, when an editor at Laurence King Publishing discovered her work online. The editor thought her graceful illustrations could work well as a children’s coloring book.
“I came back and said I would like to do a coloring book for grown-ups, and it got a bit quiet for a moment,” Ms. Basford said. “Coloring books for adults weren’t as much of a thing then.”
To convince them that it was a viable market, she drew five sample pages of detailed, mosaic-like illustrations. The publishers were sold.
“When Johanna first approached us with the idea, we knew that people would love her illustrations as much as we did, but could never have predicted just how big the adult coloring trend would be,” said Jo Lightfoot, editorial director of Laurence King Publishing.
Ms. Basford spent the next nine months working on the book at night and freelancing as an illustrator during the day. Occasionally she had doubts. “I was worried that coloring for adults was silly and it was just me that wanted to do it,” she said.
It turns out she was far from alone. Other entries to this small but growing category include Patricia J. Wynne’s lavish, nature-themed Creative Haven coloring books — discreetly described as being “designed for experienced colorists” — and the more explicitly titled “Coloring Books for Grownups,” released by Chiquita Publishing. A subspecies of these books promote the meditative aspects of coloring and doodling, including “Color Me Calm” (subtitle: “A Zen Coloring Book”) and books that promise “Easy Meditation Through Coloring.”
Major publishers are seizing on the trend. This year, Little, Brown will release four illustrated coloring books for adults, all subtitled “Color Your Way to Calm.” The books, “Splendid Cities” by the British artists Rosie Goodwin and Alice Chadwick and three titles by the French illustrator Zoé de Las Cases, feature detailed cityscapes with famous landmarks, cafes and street life. Promotional materials for the books emphasize the health benefits of “mindful coloring,” noting that the activity “has been shown to be a stress reliever for adults.”
Ms. Basford is now working on her third book, after soliciting suggestions for themes from fans. A vocal faction has requested an ocean-themed coloring book. “I’ve been drawing starfish and seahorses this afternoon,” she said.
In the meantime, “Secret Garden” has sold out in many markets, to the consternation of fans. Laurence King is reprinting 75,000 copies for the United States.
This month, Ms. Basford tried to calm her followers with a post on her Facebook page, promising that newly printed books would be shipping in a few weeks: “Don’t panic! New stock of Secret Garden and Enchanted Forest is on its way!”
Some were not placated. “WEEKS?” one frantic follower replied. “I can’t possibly wait WEEKS!”