It’s been quite a week (or two) for Carl-Johan Forssen Ehrlin. The author of a heretofore unknown Swedish picture book, which mysteriously shot to the top of Amazon’s U.K. print bestseller list on August 13, now has a bona fide hit on his hands. The question that remains, though, is how Forssen Ehrlin’s 28-page book, The Rabbit Who Wants to Fall Asleep, became, literally, an overnight success.

Forssen Ehrlin self-published through Amazon’s CreateSpace, releasing an English-language edition of the book in the U.S. in April 2014. Rabbit’s quick rise to international attention seems to have been sparked by an August 14 article in the U.K. newspaper the Daily Mail. The article credited the book’s success to Forssen Ehrlin’s claim that the title could ease parents’ bedtime routine; its headline referred to the “book that’ll send your kids to sleep.” The Mail article also noted that Rabbit had accomplished a remarkable feat, becoming the first self-published book to hit #1 on Amazon’s U.K. print list.

The Mail article then begot other coverage, with stories about Rabbit following in Forbes, the Guardian, PW, and NPR, among others. Fewer than seven days after the Mail story, with sales of the book skyrocketing, Forssen Ehrlin signed with the Salomonsson Agency, the powerful Swedish literary agency that represents such authors as Jo Nesbø. By the end of last week, PW learned that Random House paid seven figures for world English rights to Rabbit and two sequels. (At press time, no one at Random House would confirm the deal, though.)

There’s little question that the press attention the book has received—much of it seizing on the fact that the author self-published, and questioning whether the book really is the literary equivalent of pediatric Ambien—drove recent sales. In the U.S., Nielsen BookScan, which captures roughly 80%–85% of print sales, reported that Rabbit had sold 24 copies in the week ended August 16. By the following week, ended August 23, the title had sold more 29,000 copies. (Prior to August 23, BookScan shows the book sold roughly 300 copies in the U.S.)

In the U.K., print sales of the book picked up earlier, but show a similar trajectory. According to BookScan (which also tracks sales in England), the title had sold 1,150 copies in the week ended August 8. By the end of the following week, on August 15, BookScan reported that Rabbit had sold 4,119 copies. Ben Spencer, a medical journalist with one of the bylines on the Daily Mail story about the book, told PW a source tipped him off to the fact that a self-published book was perched at the top of the Amazon list.

Rabbit’s rapid rise, on Amazon’s U.K. list—without seemingly any major marketing effort—has led to speculation that sales of the title may have been manipulated. (So-called manipulation of bestseller lists is something that authors and industry members are aware of, but there are few documented instances of the practice being successful on a large scale. Nonetheless it is possible for someone who is willing to buy a large number of copies of a title over a short period to drive a book up a bestseller list, especially one like Amazon’s, which is updated hourly. In the case of Rabbit, it hit #1 on Amazon’s U.K. print list after a week in which its sales tallied just over 4,000 copies.) Amazon flatly denied this scenario, though.

“All sales activity around The Rabbit Who Wants to Fall Asleep was organic,” an Amazon spokesperson said. The spokesperson credited the book’s sudden popularity to U.K. parents talking about it on social media over the course of the summer, adding that this online chatter was the thing that “seems to be at the root of the book’s initial debut on the top 20 print list in the U.K.” Then, according to the spokesperson, once the book hit Amazon’s list, marketing and publicity efforts coordinated by the author caught the attention of the U.K. press.

According to research performed by social analytics platform Crimson Hexagon, the book was getting very little attention on blogs and social media outlets before the Mail’s August 14 story. The real jump in online mentions of the book came in the days immediately following the Mail story.

Since the book became a media sensation, Forssen Ehrlin has kept a low profile. A request made by PW, through the Salomonsson Agency, to interview the author was declined, with the explanation that Forssen Ehrlin has been overwhelmed by recent events.

Regardless of how Rabbit’s sales were initially generated, what the book’s meteoric rise proves once again is that the right kind of press attention can turn any book into a massive hit. In some ways Rabbit is reminiscent of Fifty Shade of Grey. E.L. James’s novel, which was released by a publisher so small it was considered self-published, also rode a wave of early press coverage. Both cases prove that, regardless of how the press machine gets going, once it does, it has the ability to turn a book into a phenomenon.