Published by Putnam in 2004, Betty G. Birney’s The World According to Humphrey introduced a perspicacious hamster who arrives in Room 26 as the new class pet—with no notion of what the job entails. But Humphrey swiftly gets the knack of it, settling into an adventure-filled life in his cage with a conveniently malfunctioning lock. Eleven additional middle-grade Humphrey novels followed, and on May 14, in honor of his 20th anniversary, the hamster returns in Happiness According to Humphrey, the 13th book in the series.

In earlier adventures, the hamster learns how to read, write, and shoot rubber bands (only in self-defense, of course), and develops keen observational skills and deep empathy for his human classmates, zeroing in on their problems and finding just the right ways to solve them. Birney’s latest installment reveals how Humphrey overcomes his fear of canines when he meets a gentle dog who comes to school to help his classmates with reading, another who’s impressively adept at performing tricks, and a third who has mysteriously gone missing.

Humphrey’s well-meaning antics also entertain young readers in eight shorter Humphrey’s Tiny Tales chapter books, illustrated by Priscilla Burris. These titles, along with the original series and a three-book spinoff series starring the hamster’s fellow class pet, Og the Frog, have sold more than six million copies worldwide.

The Making of a Hamster Hero

Birney told PW that she had the idea for Humphrey’s debut caper well before she began writing The World According to Humphrey, which was inspired by an incident in her own life. “My son’s elementary school had a dedicated science classroom that was filled with many animals—and the teacher wore a boa constrictor around her waist!” she recalled. “Visiting the classroom one day, I began wondering what these animals think about all that they see and hear. While other parents were focusing on their kids’ schoolwork, I was getting an idea for a book.”

As the idea of a story about a class pet took take shape, Birney pondered what species it should be. On a research trip to a pet store, she was drawn to the hamster residents, and was aware that they are popular class pets. “They were very cute, and I decided my story would feature a hamster,” Birney recalled. “But every time I started writing, the character didn’t work—he seemed old and stuffy. Over the years I kept going back to him, and one day I realized he needed a younger voice—more like the voice of a kid in the classroom. I sat down and wrote the opening page,” Birney said, “and it was the exact first page that appeared in the final book. It took me a long time to get there, but once I found Humphrey’s excitable voice—he often repeats things three times quickly—the story rolled from there.”

Like the novel’s premise, Humphrey’s name “came from a very happy memory,” the author noted. When she was a child, her grandparents lived in St. Louis—in a house on Humphrey Street.

Humphrey Earns Good Grades

The chipper class pet endeared himself to young readers and their teachers, observed Susan Kochan, senior executive editor of G.P. Putnam’s Sons Books for Young Readers, who joined the company in 1994 and has edited all of Birney’s Humphrey and Og the Frog titles. “Readers loved The World According to Humphrey from the start, and when the paperback came out in 2005, the novel really took off,” she said. “We quickly signed up another book in the series, and subsequently made multiple acquisitions.”

Humphrey proved his mettle. Birney (whose earlier writing for children’s television had won her an Emmy, three Humanitas Prizes, and a Writers Guild of America Award) received a Christopher Award for Friendship According to Humphrey, the series’ second title. Readers’ votes earned the Humphrey novels 10 state book award wins and nominations for 18 more. And the series garnered additional exposure—and a boost in sales—when it was widely featured in One School, One Book initiatives nationwide beginning in 2010.

At the core of Humphrey’s appeal, Kochan explained, is that “he is such a good observer and listener and is never judgmental. He’s a pet any child would dream of having, and kids get the sense that he is their friend, who is willing to help them with anything—and to share his own feelings.”

The editor also praised Birney’s ability to create characters and storylines that appeal to readers across a range of ages. “The grade level of Room 26 is never specified, which gives these books a more expansive audience,” Kochan said. “We often hear from teachers that the Humphrey stories’ accessible language and humor are ideal for reluctant readers. And all kids can easily identify with the classroom setting and likable characters—especially Humphrey.”

Birney credited Kochan for suggesting she create the novel that became Happiness According to Humphrey. “It had been a number of years since Betty’s prior novel, Spring According to Humphrey, and I thought it would be amazing to have a new one to mark this 20-year milestone,” Kochan said. “It was great that she was ready and willing to jump back in.”

For Birney, it was not a tough decision to make a return visit to Room 26. “I always love coming back to Humphrey.”

Happiness According to Humphrey by Betty G. Birney. Putnam, $17.99 May 14 ISBN 978-0-593-69761-0