She rejected this orthodoxy in favor of stories that better reflected the preoccupations of young children, from sensual pleasures (the shape of an apple) to visceral emotions (fear of the dark). When Brown was emerging as a writer, in the nineteen-thirties, most books for young children drew on classic fables and folktales, providing moral instruction on each page. Many readers now think of Brown titles like “ The Runaway Bunny” as tranquil introductions to storytelling, but they were radical for their time. At the age of forty-two, she died suddenly, in the South of France, after a clot cut off the blood supply to her brain. Her romances were volatile: she was engaged to two men but never married, and she had a decade-long affair with a woman.

Her friends called her “mercurial” and “mystical.” Though many of her picture books were populated with cute animals, she wore wolfskin jackets, had a fetish for fur, and hunted rabbits on weekends. Anointed by Life in 1946 as the “World’s Most Prolific Picture-Book Writer,” she burned through her money as quickly as she earned it, travelling to Europe on ocean liners and spending entire advances on Chrysler convertibles. Bruce Handy, in his 2017 book about children’s literature, “ Wild Things,” confesses that he always imagined the writer Margaret Wise Brown to be a dowdy old lady “with an ample lap”-just like the matronly bunny from her classic story “ Goodnight Moon,” who whispers “hush” as evening darkens a “great green room.” In fact, Brown was a seductive iconoclast with a Katharine Hepburn mane and a compulsion for ignoring the rules.

Goodnight moon picture book