He had mentioned how the much-beloved children's bedtime story by Margaret Wise Brown and Clement Hurd would turn 75 in September. Dr. Varner, who directs the Gayle A. Zeiter Literacy Development Center at the University of Nevada, Las Vegas, had been thinking about the reasons "Goodnight Moon" is as popular today as it was decades ago.   

"We pulled it up on our phones, and we're looking at a digital version of it together, and it's just a text that is really robust," says Dr. Varner, who focuses on literacy, language, and cultural identity. "And then family members and other folks, from the ages of 5 to over 90, all began to share memories of the importance of this book, both in their own childhoods and now and with who they are as parents. So there's this interesting intergenerational thing happening with 'Goodnight Moon,'" he says. 

Indeed, for generations this book about a great green room with a telephone and red balloon has been a part of millions of bedtime rituals, making Dr. Varner and others marvel at the aesthetic and developmental power that continues to make it a family favorite. 

The playful language excited the 5-year-old at Dr. Varner's family gathering – the kittens, the mittens, the bowl full of mush! The person over 90 recalled, too, how the black-and-white prints interspersed in a book about a "great green room" were actually meant to keep costs down. Color prints could make a picture book prohibitively expensive back then.