Lonely Leo longs for a friend—someone who sees and accepts him for who he truly is. The seeing part is the problem.

“This is Leo. Most people cannot see him,” Mac Barnett writes at the beginning of Leo. The accompanying illustration, by Christian Robinson, is of a windowed, wallpapered room with a table holding books and a candlestick phone. No Leo.

Turn the page, and that image gets a notable addition: a bow-tied boy sits under the table, reading a book. “But you can,” he writes. “Leo is a ghost.”

“One surprising thing that’s happened is, when I read that first page to kindergarteners, ‘Most people cannot see him,’ they all start screaming.‘I can! I can! I can see him!’ ”Barnett says. “It’s so amazing—it’s just a classic kid thing to do—and it’s exactly what the book is about.”

Celebrating openness, imagination, and the winning combination of mint tea and honey toast, Leo: A Ghost Story (ages 3-6) is the first collaboration by two award-winning friends: Barnett is the author of numerous acclaimed children’s and middle-grade books, including Caldecott Honor–winner Extra Yarn, illustrated by Jon Klassen. Robinson won the 2014 Ezra Jack Keats Award for New Illustrator for Rain!,written by Linda Ashman, and shared the Marion Vannett Ridegway Honor with author Renée Watson for Harlem’s Little Blackbird. They live in the same San Francisco neighborhood and met several years ago, soon after Robinson signed with their mutual agent.

“I loved Christian’s art so much, so I emailed and said, ‘Hey, I live nearby, I write picture books—want to get lunch?’” says Barnett, who’d been mulling an idea for a ghost story. “That was when I told him about Leo, really in the secret hope that he would be interested in illustrating it. In my head, [the book] looked like his art. I knew that he would treat these characters with the affection and the respect that they deserved. 

Robinson recognized Leo’s potential but not Barnett’s designs. Nevertheless, the two became fast friends—for a time, they were even on the same trivia team. (“Christian is an expert on fish,” Barnett says. “He can answer any fish question. It’s amazing.”) When the manuscript for Leo was ready, Barnett came calling.

“The first time we ever met, he mentioned the idea and was really excited about it. Then, two years later, I find out that [Leo] is written and he has me in mind to illustrate it,” says Robinson, who jumped at the chance. “From the get-go, I remember reading it and thinking, this is classic storytelling.”

A deep appreciation for classic children’s literature is something illustrator and author share—and shared in the making of Leo. Barnett drew inspiration for the story from the character-driven picture books of the 1940s-1970s: Ludwig Bemelman’s Madeline, the works of Tomi Ungerer. Those were the books that Barnett’s mother brought home from yard sales when he was growing up.

“We had books—we didn’t have a lot of money—so I feel lucky for them, the previous generation’s picture books,” he says. “That was like the golden age of American picture books. I love the kind of real, in-depth characterization and longer chapters that you get in picture books of that era, and that’s what I wanted to create—a character you really cared about, and got attached to, who had a full emotional range.”

Leo goes from melancholy to hopeful when a new family moves into his house. He makes mint tea and honey toast to welcome his potential friends, but they can’t see him to thank him. In fact, they’re scared witless.

“They hid in the bathroom and locked the door. ‘This house is haunted!’ said the man. ‘Gary, I’m scared!’ said the woman. ‘I hate tea!’ said the boy. ‘And I hate ghosts!’ ” Barnett writes.

“They did not know that Leo was floating above the tub. He heard everything they said.” 

Deciding to broaden his social options, Leo sets out into the city to roam. But when he’s finally hailed in the street by a girl chalk-drawing fantastical creatures on the sidewalk, he almost can’t believe it.

“The girl looked up and stared right at Leo. ‘I’m Jane,’ she said. ‘What’s your name?’ It was so strange to be looked at that at first Leo said nothing. Finally he replied, ‘I’m Leo.’ Jane nodded. ‘Leo, do you want to play Knights of the Round Table?’ ” he writes.

Jane and Leo’s meeting is the very first scene Robinson illustrated for the book. Leo is composed in acrylic paint and cutout paper in tones of just two colors: black and blue.

“It’s an homage to illustration of a different time—that golden period of children’s book illustration in the ’50s and ’60s,” Robinson says. “I just love that style, how the color palettes they used back in the day were so sparse, sometimes just two-color printing. I know that was because of economic reasons, but I wanted to put that challenge on myself, to work in black and blue, which seemed appropriate for a ghost story, too. It made it more fun and opened a different part of my brain in thinking of how to design and illustrate something.”

The effect may be timeless, but Leo’s new friend is a modern girl. Jane proclaims herself “king” of the Knights of the Round Table, which includes Sir Ruffs, an imaginary dog; Sir Mews, an imaginary cat; Sir Squawks, an imaginary hamster; and now, Sir Leo.

“[A mutual friend] pointed out that Leo reminds her of Mac, and that she could see Jane being me—which I don’t take as an insult,” Robinson says. “I love Jane. She’s imaginative, and she’s sassy and playful and opinionated. And I think, in a way, I did sort of see Leo as Mac and the story as my friendship with Mac.” 

Not only can Jane see Leo—she likes what she sees. And instead of playing with dolls, she’d rather sword fight with her new best friend.

“Christian is particularly great at drawing children, like the picture of Leo and Jane playing with swords,” says Barnett. “With just a few lines, he captures all the motion and the pure joy of imaginative play when you’re a kid. It connects me back to that age. He’s so thoughtful, so smart when it comes to making picture books.”

That thoughtfulness extends to ensuring the depiction of characters from different backgrounds.

“I always say that Jane is a ‘blue American,’ and what I’m trying to point out is that even though the colors of these kids are blue and white, still, diversity in children’s books is important to me,” Robinson says.

The paucity of diverse characters in children’s literature has been highlighted nationally by the Tumblr campaign #WeNeedDiverseBooks, among other organizations.

“It’s a hot-button issue, and anything I work on, I want to make sure that I’m representing kids that look all sorts of different ways—for Jane to have braids or have a mother who wears a headscarf at night....It does seem like [the industry] is slow to change, but most importantly, the discussion is happening, and it’s something that people are engaging in,” he says.

Jane and Leo’s friendship is able to bridge their differences: city to suburb, girl to boy, human to ghost. What they share is the desire to have and to be a true friend—and a taste for mint tea and honey toast.

“One thing that I’m so happy about is that we were able to put out a 52-page picture book. That doesn’t happen much anymore,” Barnett says. “It let Christian do so much art, and so it really takes the pace of the story and slows it down to where it needs to be, to where you get to feel like you spend a lot of time with both Leo and Jane—to get to know them.”