"The Hunger Games" author Suzanne Collins releasing new book in 2013

Suzanne Collins, the author who penned "The Hunger Games" trilogy, has a new book coming out next year.

The multimillion-selling children's author has completed an autobiographical picture story scheduled to be released on Sept. 10, 2013, Scholastic Inc. announced Thursday.

The 40-page book will be called "Year of the Jungle," and is based on the time in Vietnam served by Collins' father, a career Air Force officer.

"Year of the Jungle" is her first book since 2010's "Mockingjay," the last of "The Hunger Games" novels that made Collins an international sensation. More than 50 million copies of the "Hunger Games" books are in print and the first of four planned movies has grossed more than $600 million worldwide since coming out in March.

Collins' next project will be intended for ages 4 and up, a younger audience than those who have read (and re-read) her dystopian stories about young people forced to hunt and kill each other. But "Year of the Jungle" will continue, in a gentler way, the author's exploration of war. James Proimos, an old friend from her days as a television writer who helped persuade Collins to become a children's author, illustrated the book.

"For several years I had this little wicker basket next to my writing chair with the postcards my dad had sent me from Vietnam and photos of that year. But I could never quite find a way into the story. It has elements that can be scary for the audience and it would be easy for the art to reinforce those. It could be really beautiful art but still be off-putting to a kid, which would defeat the point of doing the book," Collins, 50, said in a statement released by Scholastic.

"Then one day I was having lunch with Jim and telling him about the idea and he said, 'That sounds fantastic.' I looked at him and I had this flash of the story through his eyes, with his art. It was like being handed a key to a locked door. So, I just blurted out, `Do you want to do it?' Fortunately he said 'Yes."'

"How could I refuse?" Proimos said in a statement. "The idea she laid out over burritos and ice tea during our lunch was brilliant and not quite like any picture book I had ever come across. The writing is moving and personal. What Suzanne does so well here is convey complicated emotions through the eyes of a child."

According to Scholastic, "Year of the Jungle" will tell of a little girl named Suzy and her fears after her father leaves for war. She wonders when he'll come back and "feels more and more distant" as he misses family gatherings. He does return, but he has changed and his daughter must learn that "he still loves her just the same."

Collins has said before that she wanted to write a book about her father. In a 2010 interview with The Associated Press, she explained that her father was a trained historian who made a point of discussing war with his family.

"I believe he felt a great responsibility and urgency about educating his children about war," she said. "He would take us frequently to places like battlefields and war monuments. It would start back with whatever had precipitated the war and moved up through the battlefield you were standing in and through that and after that. It was a very comprehensive tour guide experience. So throughout our lives we basically heard about war."

Scholastic also announced Thursday that "Catching Fire," the second "Hunger Games" book and originally released in 2009, is coming out in June as a paperback. The paperback edition usually comes within a year of the hardcover, but "Catching Fire" had been selling so well that Scholastic waited. "Mockingjay" has yet to be released as a paperback.

Next summer, Collins' five-volume "The Underland Chronicles," published before "The Hunger Games," will be reissued with new covers.

"'The Underland Chronicles,' with its fantasy world and 11-year old protagonist, Gregor, was designed for middle readers," Collins said in a statement. "The 'Hunger Games' trilogy features a teen narrator, Katniss Everdeen, and a stark dystopian backdrop for the YA (young adult) audience. 'Year of the Jungle' attempts to reach the picture book readers by delving into my own experience as a first grader with a father deployed in Vietnam."