During Mordicai Gerstein’s fifth year of life, he started kindergarten, his little brother was born and he faced a whole range of other experiences and changes for the first time. Now, over 70 years later, he still remembers the events of that year almost exactly.

Strange as it sounds, this ability has come in handy during his decadeslong career as a writer and illustrator. In fact, Gerstein’s newest book, The Night World, is based on a specific incident from that year.

Gerstein recounts the story thoroughly. He awoke in the middle of the night, needing to pee, and called for his father, who then carried him through the house to the bathroom. On that journey, Gerstein was concerned by how different everything looked in the dark. “Where the back yard should’ve been there was this weird, colorless world with strange grey and black shapes,” he recalls. Though his father explained that the unnerving landscape was still the back yard, Gerstein declared it “the night world” and decided he wasn’t yet ready for it.

In The Night World, the series of events plays out quite differently. A boy, awoken by his cat, moves through the pre-dawn darkness of his home—a journey Gerstein renders almost entirely in grey and black. But unlike the author, the picture book’s protagonist learns that the night world isn’t so scary after all; instead he finds it inviting. After exploring the house, the boy goes out into the yard, where he watches the sunrise and Gerstein’s art bursts into full color.

Perhaps unsurprisingly, Gerstein’s background is in fine art. He attended art school intending to become a painter but ended up taking a job as an animator after graduation. In addition to making animated films, he began drawing cartoons, and Elizabeth Levy eventually approached him to illustrate her mystery Something Queer Is Going On. The book became a series, and Gerstein fell in love with illustrating.

It was many years before he started writing his own stories, however. Gerstein had never considered himself as a writer and had no idea how to go about crafting a narrative. “I thought you had to have all of these ideas in your head,” he says, “and you would just transcribe them.” Nonetheless, he was committed to writing, and, after almost a decade of false starts, his stories started coming. They haven’t stopped since.

Though Gerstein enjoys the thrill and (relative) newness of writing, illustrating remains a vital part of his process. The Night World’s remarkable balance of strangeness and comfort would be impossible without his striking images. To create the book’s nighttime look, he employed a very different technique than that he’s accustomed to: instead of carefully tracing out the images in pen and then adding color, he jumped right into painting, brushing black paint onto grey paper as he searched for the shapes he wanted.

Gerstein describes painting and writing as the process of finding the story in the pages. “I think of a picture book as a place. Each book is a different world,” he says. “I wanted to put that night world between covers.” Now it will go out into the world to have a life of its own.

On the cusp of his 80^th birthday, Gerstein still finds this process exciting. “I feel like I’m enjoying it more than ever,” he says. “I feel like I’m really getting the hang of it.”

Alex Heimbach is a freelance writer in California.