Something remarkable happened today. A children’s book hit the No. 1 spot on Amazon.com’s best-seller list. And it did so a month before the book is even slated for release.

You may have heard of the book–it’s a best-seller after all. Go the Fuck to Sleep by Adam Mansbach, began its life as a joke Facebook post in June. It was a particularly trying instance of bedtime with his 2-year-old daughter, and Mansbach let off some steam in the form of a humorous status update to his friends: “Look out for my forthcoming children’s book, ‘Go the — to Sleep.’ “

The response from his friends was so fierce that Mansbach decided to make his joke book a real one. Go the Fuck to Sleep, which he bills as a “children’s book for adults,” will hit stores on June 14, published by the Brooklyn press Akashic. If it’s not even due for a month, though, how did a little 32-page book already snag a film option deal with Fox 2000 and, today, reach the pinnacle of online publishing commerce world?

The answer appears to be piracy.

There are many reasons why Go the Fuck to Sleep deserves to be a best-seller, and probably would have attained that status anyway. It’s hilarious. It’s honest. Humor books tend to do well in general, as do parenting books, as do short books. Not to mention it’s the perfect ironic, light-hearted shower gift. Parental exhaustion is by no means an emotion exclusive to Mansbach. The book “just tapped into this nerve,” Ibrahim Ahmad, Akashic senior editor, told The Bay Citizen in its excellent report on the phenomenon.