As a kid, Holly Goldberg Sloan was convinced that New Year’s should be celebrated in June. There was no point in marking Day 1 on January 1, she believed; instead, it was summer, when school was out and the weather was nice, that big changes really happened.

“Summer is a break from our real life,” she told KidsPost last week, speaking from her home in sunny Santa Monica, California. “The days are long, the food’s a little better and people seem not as cranky. Also, by the time

Holly Goldberg Sloan is the author of ”Short," a middle-grade novel about a vertically challenged girl who appears in a summertime production of "The Wizard of Oz." The title is part of KidsPost’s 2017 Summer Book Club. (Victor Goodpasture)

you get to April and May, the teacher you had is so sick of you and you’re so sick of them. You’re set free.”

Sloan, 58, went on to write and direct television shows and movies in part because of all the TV she watched one summer long ago. You may have seen her Disney movies “The Big Green,” about soccer, and “Angels in the Outfield,” which she wrote before penning books such as “Counting by 7s” and “Appleblossom the Possum.”

But she says no summer was as significant as the one between fourth and fifth grades, when her architect mother made her audition for a production of “The Wizard of Oz” at the local college.

Holly, the shortest girl in her class from kindergarten through seventh grade, was cast in the musical as a Munchkin. She was shocked.

She had already been “fired” from piano lessons — to fool her parents, she played a recording of herself practicing so that she could read a Nancy Drew mystery novel instead — and had been held back in ballet class, which she promptly quit.

Her “Oz” experience, working with a director who helped her believe in herself, forms the basis for her new book, “Short.”

The novel, published in January, tells the story of a vertically challenged girl named Julia Marks who is cast in a production of “Oz,” just as Sloan was. While working on the show, she befriends a trio of adults: the musical’s director, Shawn Barr; Olive Cortez, a fellow Munchkin with dwarfism, a condition that makes a person very small; and Mrs. Chang, a talented costume designer who turns out to be much more than a “boring old lady who spent a lot of time growing flowers,” as Julia once thought.

With their help, Julia starts to learn to embrace her height and the differences that make each person special.

“We all have a challenge,” Sloan says, be it height or even hair color. “What would the world be if we all looked exactly the same, dressed exactly the same and had the exact same skills and talents? Life just wouldn’t be worth living.”

Sloan grew six inches in six months while she was in middle school and now stands at 5-foot-7. Recently, she said, a boy tracked her down outside his school, where she was scheduled to give a talk.

Was there a secret? he asked. Any special “beans or pills” that might make him grow tall?

There are no magic beans, Sloan recalls telling him. But, she added: “I do have a secret, and that’s to go out and do the thing that scares you. And you’ll grow in the end.”

“But he wasn’t buying it,” Sloan says. “He just kind of scowled and walked back into the school. But the kid who sneaks out of school to find the right person, I’m not worried about him. He’s finding his voice and fighting back.”

(Marvin Joseph/The Washington Post)