The originally self-published Swedish children’s book The Rabbit Who Wants To Fall Asleep may seem to be an overnight sensation, but its success, claims author Carl-Johan Forssen Ehrlin, is actually the result of a slow build over roughly five years. According to Ehrlin, the sudden spike in international sales for the book—which Random House Children's Books bought for seven figures in August and released on Friday—is thanks to a perfect storm: word-of mouth praise driven by e-book giveaways, coupled with Amazon U.K. providing entrée to consumer media once the self-published book had taken off.

During a phone interview with PW from the New York City office of his new publisher, Ehrlin, 37, who received a B.A. in psychology from Jonkoping University in Sweden, has no formal training in pedagogy or any direct experience working with children. But he has worked with adults, as a communications expert and management coach, and said the idea for writing Rabbit about five years ago and self-publishing it in 2011 in Sweden was driven by his experience working with this group.

Rabbit marks Ehrlin's third foray into publishing. In 2006 he self-published Create Your Future, about self-development. He also wrote a book for the Nordic media group, Sanoma, that he described as “student literature” that touches on subjects like personal involvement and leadership.

“I’m good at communications,” he said. “I used my experience helping adults, I put all that in [Rabbit]. I had to follow this idea and see where it could lead me, if I could really help all these children.”

Initially, Ehrlin focused on selling Rabbit at seminars he conducted before various groups and the classes he taught at Jonkoping University. The word-of-mouth praise that effort drove, he said, resulted in people talking about the book to the press. This, he said, propelled sales of the book in Sweden. After Rabbit became a bestseller in Sweden, Ehrlin decided to solicit “friends and their friends” to assist him in translating the book into approximately half a dozen languages so that it could reach a wider audience.

After the various translated editions were self-published in 2014, through Amazon’s CreateSpace imprint, the U.K. edition, Ehrlin said, received “the most attention.” This, he assumes, is attributed to the the fact that he gave away e-book editions of the title via Facebook.

"I did some ads there saying the book existed and [people] could try it for free and see if they liked it or not."

Ehrlin thinks that the people who downloaded the free e-books must have recommended the title to their friends, and those friends then sought out the print edition. “There was a correlation there” between the growing number of free downloads and sales of the print book," he noted. “Then the snowball started rolling, I think. There was a lot of word of mouth.”

As Rabbit climbed Amazon U.K.’s bestseller list, executives there took notice. “They saw something big was happening; they had never had that experience before,” Ehrlin said, disclosing that Amazon had to “bring in more printing machines” and staff worked around the clock to meet the growing demand for the POD book.

“They wanted to help me,” he explained, noting that the tipping point was when the book landed at #3 on Amazon's U.K. print bestseller list. That help came in the form of media access; Amazon put the author in touch with outlets including the Daily Mail, the Telegraph, and the Guardian; all of those papers then ran stories about the self-published picture book that became the first indie title to top Amazon U.K.'s print bestseller list.

Ehrlin estimates that, actually, it was the day after the Daily Mail ran its story on Rabbit that the title became Amazon U.K.'s #1 bestseller. A few days later, it was topping Amazon bestseller lists in the U.S. and other countries.

As Amazon struggled to keep up with demand for the book, Ehrlin was inundated with more media requests as well as offers from publishers—more than 300 said they wanted to publish the book. He also received offers of representation from literary agencies, including Sweden’s prestigious Salomonsson Agency.

He wound up signing with Salomonsson, which brokered his seven-figure deal with Penguin Random House. As part of the agreement, he is under contract for two more books that “will also help children get to sleep.”

Ehrlin, who has a two-year-old son, is confident that there will be an audience for his next two projects. Fans, he said, have been contacting him and asking for more bedtime stories. He said the fans complain that “it’s getting boring to read the same story over and over again.”

What about the parents who find the book’s promise to be an empty one? Ehrlin insists that Rabbit is “just a recommendation that you can work with.” Some parents, he said, take the book's instructions, and implicit promise, "a little" too literally.

"You can adapt the story," Ehrlin added. “Observe [the child] and adapt, [that's] what I recommend to parents.”