NEW YORK • At a reading in New York last month, Pulitzer Prize- winning novelist Jane Smiley faced an unruly crowd as she read from her new book, Twenty Yawns.

"The beach umbrella was flapping in the breeze," she read. "Flap, flap, flap."

"Look, a fly!" a little boy in a Spider-Man T-shirt yelled, swatting at a buzzing insect.

Smiley took the outbursts in her stride and tried to engage an audience that consisted mostly of toddlers and their minders as she read the story, about a girl who struggles to fall asleep after a day at the beach.

"Do you know how to look sleepy?" she asked. The children flopped over and pretended to snore.

For most of her career, Smiley, 66, has tried to avoid putting readers to sleep. Now, with her first picture book, she is joining a handful of well-known novelists who are aiming to reach readers so young that they probably appreciate the pictures more than the prose.

A cluster of new picture books from famous writers will hit bookstores in the coming months, including a lighthearted poetry collection by Calvin Trillin and a creepy, fairy tale-like picture book in translation from the mysterious, pseudonymous Italian author Elena Ferrante, who is best known for her four-part Neapolitan series.

"Every year, there are adult writers and celebrities who choose to write in the genre, but this is a particularly high-calibre group," said Ms Megan Tingley, executive vice-president and publisher of Little, Brown Books for Young Readers.

The current crop of picture books from literary writers is arriving at a moment when children's literature has become a vibrant and often lucrative niche for novelists.

Revenue from children's books sales ballooned to US$1.7 billion (S$2.3 billion) last year from US$1.5 billion in 2011, according to the Association of American Publishers, which tracks sales from more than 1,200 publishers.

Sales of adult books, by comparison, remained stagnant.

Following the blockbuster success of series such as Twilight, a growing number of best-selling authors have migrated into the booming market for young adult and middle-grade fiction, including James Patterson, John Grisham, Smiley and Jennifer Weiner.

Picture books, typically written for three- to seven-year-olds, could represent the next frontier for writers seeking to further expand their audiences by reaching an even younger demographic. It also may help them hook impressionable young readers - sometimes before they can even read.

Some prominent authors have turned to picture books late in their careers, motivated, in part, by the desire to write something their grandchildren could appreciate.

"I tried to see things from their point of view," said Trillin, who decided to write a picture book a few years ago, when he found himself spontaneously composing funny rhymes for his grandson.

The resulting collection, titled No Fair! No Fair! And Other Jolly Poems Of Childhood, includes 14 whimsical poems, with illustrations by cartoonist Roz Chast. The poems address childhood injustices such as being denied ice cream for breakfast.

Smiley said her book had the desired effect on her grand- daughter, who turns two this year: "She fell asleep."

Others have taken up the craft as a social mission.

Poet and novelist Sherman Alexie, who is publishing his first picture book, Thunder Boy Jr, this month, said he wanted to write a picture book that featured a Native American protagonist - a rarity in children's literature. He also hopes to reach children at the moment when they are just discovering the addictive pleasures of books.

"I always hope my book becomes the gateway drug to reading, so I was thinking, why not aim for even younger?" said Alexie, who has also published an acclaimed young- adult novel.

Writing children's literature has always appealed to a subset of serious novelists.

James Joyce, who wrote some of the most famously impenetrable passages in English literature, wrote two children's fables about cats for his grandson.

James Baldwin, John Updike and Kurt Vonnegut all published illustrated books for young readers.

Still, it remains unusual for contemporary novelists to write text for picture books. Many still see the books as unsophisticated and pedantic - more of a sleep aid or a tool to teach literacy rather than a place to showcase elegant prose.

It can also be a daunting genre for writers to break into.

Classics by beloved authors such as Dr Seuss still sell millions of copies a year, diminishing the appetite for new titles.

But lately, there have been signs that picture books are entering a new golden age. Authors are pushing the aesthetic boundaries of the form, with playful works such as B.J. Novak's The Book With No Pictures, a pictureless picture book that has become a runaway hit, with more than a million copies in print.

Once considered a stagnant category, picture books made up about 14 per cent of the market for children's books last year, but accounted for nearly 40 per cent of the 100 top-selling children's books - up from 15 per cent in 2005, according to Nielsen.

While the prose can seem deceptively simple, a well-written picture book is not easy to pull off.

"It's easy to dismiss picture books because they're short, but it's really hard to write a meaningful and enduring text that withstands repeated readings," Ms Tingley said.

It took Alexie about 70 drafts before he was satisfied with Thunder Boy Jr, which is narrated by a Native American boy who wants a different name. He wrestled with how to write convincingly in the voice of a young boy and how to pack complex ideas about race and identity into a short, simple story.

"The difficult thing was to find a story that could hold socio-political meaning for the parents and the kids and blend it all together into a book that a five-year-old wants to read again and again," said Alexie.

For Smiley, who has published 16 novels, including A Thousand Acres, one challenge of writing Twenty Yawns was letting the images speak for themselves and cutting down on the descriptive prose, she said.

But mostly, the story was a breeze. "It doesn't have a plot," Smiley said.

She is already working on a sequel, Twenty Bites.

At the reading last month at Bank Street Bookstore, children offered their own assessments.

"It's a little funny book," a boy said, as he handed Smiley a book to sign.

"Is it a little book that's funny or a book that's a little funny?" she asked as he scampered off.

By then, a bookstore employee had produced a basket of teddy bear-shaped cookies, and the impromptu literary salon broke up.

NEW YORK TIMES