IN MY LIBRARY Wendy Whelan

What’s the expiration date for a dancer? That’s the underlying question behind “Restless Creature: Wendy Whelan.” Out May 24, the documentary focuses on the Kentucky-born ballerina, who started ballet lessons at 3, joined New York City Ballet at 17 and later, as a principal, was featured in groundbreaking works by George Balanchine, Jerome Robbins, Twyla Tharp and many more. About five years ago, though, she was asked to hang up her toe shoes. “I’m now doing contemporary work,” Whelan, 50, told The Post. “I have to keep dancing for my spirit, my body, my mind.” Here are her favorite dance books.

Repertory in Review: 40 Years of the New York City Ballet by Nancy Reynolds

As soon as I got into the company, I came across this thick book. It’s filled with information about all the Balanchine ballets: their history, who danced them originally, who famously danced them after. Balanchine’s ballets are often abstract. This gives you a look inside them.

A Very Young Dancer by Jill Krementz

I got this book when I was 9 and dancing in “The Nutcracker” in Louisville. To see these pictures of 9-yearolds dancing in the New York City Ballet! I looked at that book all the time. Six years later, I was at the School of American Ballet, and some of those kids became my friends.

I Was a Dancer by Jacques d’Amboise

When I moved to New York at 15, I actually lived in Jacques’ home for about four years, with his wife and twin daughters, both of whom were in “A VeryV Young Dancer.” Jacques is a living legend. He wrote this book late in life, but it was worth the wait: It’s just filled with color and intrigue about his life and his dance institute. He has a huge story to tell, and he tells it well.

Once a Dancer by Allegra Kent

A lot of people think she was Balanchine’s favorite dancer. She had a butterfly quality and a rich imagination. She even created her own name. Hers is actually Iris Cohen. The way she puts words together is similar to how she put steps together.