Go the F**k to Sleep is without a doubt one of the most written-about books of the year so far. Due out from Brooklyn indie publisher Akashic Books June 14, it has already leapt to the top of Amazon’s bestseller rankings and has more than 275,000 copies in print. Written by Adam Mansbach and illustrated by Ricardo Cortés, the sassy, profanity-sprinkled parody of a children’s bedtime book has attracted a flood of pre-pub attention across media venues—which shows no sign of ebbing. Today, Macmillan Children’s Books threw a new spotlight on the picture book with an announcement claiming strong parallels between Mansbach’s book and It’s Time to Sleep, My Love, a bedtime book featuring a lullaby by Eric Metaxas and art by Nancy Tillman, released by Feiwel and Friends in 2008.

Jean Feiwel, senior v-p and director of Macmillan Children’s Publishing and publisher of Feiwel and Friends and Square Fish, expresses amazement that no one has publicly picked up on the similarities between the two books. “The moment I saw Go the F**k to Sleep, after I stopped laughing, I said, ‘Wait a minute!’ This is clearly a parody of It’s Time to Sleep, My Love,” she says. “Except for the profanity laced throughout, the book has the same kind of lilting lullaby as Eric’s, and the art style is the same as Nancy’s. I can’t believe no one has made the connection.” There are currently almost five million copies of Tillman’s six children’s books in print.

Macmillan’s press release compares sample lines from It’s Time to Sleep, My Love (“It’s time to sleep,/ it’s time to sleep,/ The fishes croon in waters deep./ The songbirds sing in trees above,/ It’s time to sleep, my love, my love.”) and Go the F**k to Sleep (“The windows are dark n the town, child./ The whales huddle down in the deep./I’ll read you one very last book if you swear/ You’ll go the f**k to sleep.”). The release also presents side-by-side images of a spread featuring Tillman’s art and Cortés’s cover art, both of which depict sleeping tigers (one tiger in the first instance, and several in the second).

Mansbach, the 2010-2011 New Voices Professor of Fiction at Rutgers University and author of two acclaimed novels, The End of the Jews and Angry Black White Boy, who told PW he was inspired to write Go the F**k to Sleep by his own experiences attempting to get his daughter to sleep, says he is not familiar with It’s Time to Sleep, My Love. “There’s a similarity among any number of bedtime books in rhythm and tone, and in the imagery used,” he observes. “I didn’t base this book on any one children’s book.”

Johnny Temple, publisher of Akashic Books, notes that he, too, is unaware of the Metaxas-Tillman collaboration and was surprised to hear of the comparisons: “That’s bizarre. In fact, I know specifically what led to the sleeping tigers picture, and it had nothing to do with another book.” The publisher says that foreign rights to Go the F**k to Sleep have sold to 11 countries, “with another seven offers on the table. This book really strikes a chord with parents around the word. It provides a humorous outlet for them and lets them understand they’re not alone.”

Feiwel agrees, saying, “The book does capture a hysterical, freak-out moment that every parent can relate to, and it is funny. But it’s not just based on ‘classic’ children’s books, which article after article has mentioned. It’s based on Eric’s and Nancy’s book. It takes that book’s sentiment and turns it on its head. That’s obviously OK for an adult book to do in a clever way, but I just wanted to say, ‘Back up. It’s Time to Sleep, My Love was there first.’ Let’s give credit where credit is due.”