When Margaret Wise Brown began to write for young children, most picture books were written by illustrators, whose training and talents lay mainly in the visual arts. Brown, the author of Goodnight Moon, was the first picture-book author to achieve recognition as a writer, and the first, according to historian Barbara Bader, "to make the writing of picture books an art."

After graduating college in 1932, Brown's first ambition was to write literature for adults; but when she entered a program for student teachers in New York, she was thrilled by the experience of working with young children, and inspired by the program's progressive leader, the education reformer Lucy Sprague Mitchell. Mitchell held that stories for very young children should be grounded in "the here and now" rather than nonsense or fantasy. For children aged two to five, she thought, real experience was magical enough without embellishments.

Few children's authors had attempted to write specifically for so young an audience, but Brown quickly proved herself gifted at the task. She was appointed editor of a new publishing firm devoted to children's books, where she cultivated promising new writers and illustrators, helped develop innovations like the board book, and became, as her biographer Leonard S. Marcus notes, "one of the central figures of a period now considered the golden age of the American picture book."

Though Brown was intensely interested in modernist writers like Gertrude Stein (whom she persuaded to write a children's book, The World Is Round), it was a medieval ballad that provided the inspiration for The Runaway Bunny (1942), illustrated by Clement Hurd. The Runaway Bunny was Brown's first departure from the here-and-now style of writing, and became one of her most popular books.

Goodnight Moon, another collaboration with Hurd, appeared in 1947. The story of a little rabbit's bedtime ritual, its rhythmic litany of familiar objects placed it somewhere between the nursery rhyme and the here-and-now story. At first it was only moderately successful, but its popularity gradually climbed, and by 2000, it was among the top 40 best-selling children's books of all time.

The postwar baby boom helped propel sales of Brown's many picture books, including Two Little Trains (1949) and The Important Book (1949). After the author died in 1952, at the age of 42, many of her unpublished manuscripts were illustrated and made into books, but Brown remains best known for Goodnight Moon and The Runaway Bunny.

More people recognize those titles than recognize the name of their author, but Margaret Wise Brown wouldn't have minded. "It didn't seem important that anyone wrote them," she once said of the books she read as a child. "And it still doesn't seem important. I wish I didn't have ever to sign my long name on the cover of a book and I wish I could write a story that would seem absolutely true to the child who hears it and to myself." For millions of children who have settled down to hear her stories, she did just that.