During her lifetime, Margaret Wise Brown was dubbed “the laureate of the nursery.” Today, she remains among the most beloved — and best-selling — children’s authors of all time. In her relatively brief 15-year career, Brown wrote more than 100 books, including the classic bedtime stories “Goodnight Moon” and “The Runaway Bunny.” Since its publication in 1947, “Goodnight Moon” has sold millions of copies and continues to be a staple in libraries and homes around the world.

Margaret Wise Brown at Stafford House on Cumberland Island, holding her first copy of “Fox Eyes,” illustrated by Jean Charlot. (Jim S. Rockefeller Jr.)

Brown’s turbulent personal life, however, was hardly the stuff of a children’s book. Born into wealth and privilege in New York in 1910, Brown was beautiful, athletic, adventurous and restive. She had relationships with men and a woman. In March of 1952, it appeared that Brown finally had found love when she met the much-younger James Stillman Rockefeller Jr. They made plans to marry later that year, but the union never occurred.

Brown died suddenly, at the age of 42, when she was recovering from emergency surgery in France. In a characteristically impetuous move, Brown kicked up her leg to show doctors how much better she felt, loosening a blood clot that killed her almost instantly.

A new biography, “In the Great Green Room,” brings renewed attention to the contrast between Brown’s private life and her status as a celebrated children’s author. Drawing on personal letters and diaries, author Amy Gary draws a colorful — if oddly speculative — portrait.

“In the Great Green Room: The Brilliant and Bold Life of Margaret Wise Brown,” by Amy Gary (Flatiron)

Gary highlights Brown’s pioneering role as a picture book author as well as her work with major children’s book writers and illustrators such as Garth Williams (“The Little Fur Family”), Leonard Weisgard (the Caldecott Medal-winning “The Little Island”), and Clement Hurd (“Goodnight Moon” and “The Runaway Bunny.”) She also credits Brown for paving the way for the publication of Gertrude Stein’s quirky children’s book “The World Is Round.”

But Gary is most fascinated by Brown as an individual. We learn of Brown’s natural athleticism — she once won the national title of the fastest woman in the sport of beagling, where humans run with the hounds. Gary also writes of Brown’s extravagant spending, such as the time that she used her first payment as an author to purchase a street cart full of flowers to decorate her apartment in celebration of her burgeoning literary career.

Brown’s friends gave her various nicknames. Her high school classmates called her “Tim” for the timothy (or hay)-like color of her hair, while her colleagues at the Bank Street College of Education tagged her “Brownie.” Brown also was given to breaking rules, and Gary details how she nearly was expelled from her boarding school just two weeks before her high school graduation for an illicit early-hour trip to a nearby town.

Gary gives particular attention to Brown’s long-running affairs with two people who repeatedly hurt her. One was a serial womanizer named William Gaston; the other was one of Gaston’s sometime lovers, Michael Strange (born Blanche Oelrichs, a former wife of John Barrymore), a mediocre actress and poet who dismissed Brown’s literary success because she wrote for children. This was especially cruel, as throughout her life, Brown aspired to write for adults.

Clearly Gary has plenty of material with which to fashion a page-turner of a biography. Yet there’s a troubling lack of attribution to many of Gary’s observations. Here, for example, is a passage about Brown sitting alone in the British countryside: “As the English mist swept around her, she reconsidered. The problem wasn’t her style of writing, she realized; it was that she couldn’t think up anything of importance to write about.” Later Gary writes of a time when Brown and Gaston went sailing together. “Margaret nestled in closer to Bill, thrilled to be in his arms in the fresh air and on the exciting seas of her beloved Maine.”

This novelistic style — a stark contrast to the tone of Leonard Marcus’s 1992 biography, “Margaret Wise Brown: Awakened by the Moon” — is sometimes distracting and puzzling. Gary writes in her introduction that she spent years working with Brown’s papers, including her diaries and letters, which she found in a trunk in the attic of Margaret’s sister’s barn. Why not quote from those so we can hear Brown’s voice directly? Instead, Gary gives us just a few samples — poems, a recipe, a ballad.

Still, as we prepare to celebrate the 75th anniversary of “The Runaway Bunny” and get a first peek at Brown’s never-before-published picture book “North, South, East, West” later this month, it is gratifying to be reminded again about what a fascinating woman and a gifted writer Margaret Brown was.

Karen MacPherson is the children’s and teen services coordinator for the Takoma Park Maryland library.

in the great green room
The Brilliant and Bold Life of Margaret Wise Brown

Flatiron. 305 pp. $26.99