If there is a moral at the heart of George Elliott’s first children’s book, it’s that monkeys are fun and that doing some things to excess out of sheer enthusiasm is not all that bad when you’re a kid.

The boy in the title is Matthew, a typically obsessive and inquisitive child, complete with Hawaiian shirt, shorts, and a baseball cap permanently affixed to his head. During a visit to the zoo with his parents, he encounters monkeys playing in their cage and eating banana after banana. That night, Matthew decides he will eat only bananas (and banana bread, banana muffins, banana chips, and so on). After two weeks of this banana-only regimen, he “transmogrifies” into a monkey.

At that moment, it looks as if this will be a cautionary tale about the importance of moderation, but Mississauga, Ontario, writer Elliott pulls a very subtle switch by having a host of doctors and psychiatrists and other experts tell Matthew’s parents that “he will stop being a monkey when he wants to stop being a monkey.” In other words, relax and let him be a kid. And they’re right, because soon Matthew gets an outsized hankering for peanuts and becomes an elephant.

Andrej Krystoforski, an artist in Richmond Hill, Ontario, captures well the book’s theme of the pleasures of simple goofiness with his bright, energetic pen-and-watercolour illustrations. Matthew’s parents are rendered as bland, slightly yuppified drips, which is fairly appropriate, but Matthew himself is all boyish id, with a big grin, big ears, and a big head. Krystoforski makes certain that many of the minor background characters are silly and vibrant, too, exactly as they would appear to a boy with a frantic imagination and a desire to pursue his enthusiasms to their ends.