Hello everyone! You may remember when I posted an image of The Underwearwolf, a picture book by Gideon Sterer, to my Instagram, Threads, Twitter and Bluesky in April. In those posts, I announced that I was invited to review an advance reading copy of the book ahead of its release date by Simon & Schuster. Well, with the book’s recent release, I am happy to share my review! Be sure to get it on Amazon today! You can also check out Sterer’s website at this link! Below is the book’s synopsis:
Perfect for fans of Creepy Pair of Underwear, this wolfish picture book romp follows a kid who finds himself in a hairy situation when he dons a pair of not-so-normal undies under the light of the full moon.
Do not, under any circumstances,
Or for any reason,
Wear this underwear under the full moon.Do you understand?
Get ready to howl with laughter as one rule-breaking, underwear-loving kid transforms into a—gasp!—UNDERWEARWOLF! Now he’s on an unforgettable nighttime adventure that may or may not include furry paws, sharp claws, uncomfortable wedgies, and an honest-to-goodness wild wolfpack! No butts about it—this is one read-aloud that’ll blow your undies off!
I’m glad to have been given this opportunity after my previous review of Little Ghost’s Summerween! But before we begin, I would like to give a heads up to some spoilers to the book. Let’s try not to get too spooked by these pages, shall we?
Background
In April 2026, I received a message from Thad Whittier of Simon & Schuster, who told me that he was reaching out to discuss a possible review, interview, or feature for The Underwearwolf by Gideon Sterer. According to the book’s jacket, Sterer is the New York Times bestselling author of The Christmas Owl, I Will Read to You, From Ed’s to Ned’s, Not Your Nest!, The Night Knights, and The Midnight Fair, among others. Gideon grew up in upstate New York, where his parents owned a little zoo in which he would run around after hours and let the animals out. He now lives in New York City and invites you to visit him online at gideonsterer.com and on Twitter at @gideonsterer.
Also according to the book’s jacket, Charles Santoso, the book’s illustrator, loves drawing little things in his little journal. He gathers inspiration from his childhood memories and curiosities he discovers in his everyday travels. He has illustrated several picture books, including The Snurtch, I Don’t Like Koala, Finding Muchness, and Ida, Always. Charles also works as a visual development artist, creating illustrations for feature film projects. He lives and works in Singapore. You can visit him at CharlesSantoso.com.
Whittier told me that in The Underwearwolf, Creepy Pair of Underwear meets Mr. Tiger Goes Wild in this laugh out loud picture book about a kid who finds himself in a hairy situation after breaking the one rule that really should not be broken. What follows is a wildly funny, slightly spooky nighttime adventure full of furry paws, sharp claws, wild wolfpack energy, and plenty of underwear fueled chaos. The Underwearwolf is a perfect fit for Halloween roundups, Summerween coverage, new release roundups, & funny picture book features.
Whittier also thanked me for my consideration, and to please let him know if I’d like a finished copy or if I’d like to coordinate an interview with Sterer or Santoso. To receive a book review request from a major publisher such as Simon & Schuster was an honor, so I thanked Whittier for reaching out and told him that I really appreciated the opportunity to review The Underwearwolf, and that I’d be happy to receive a finished copy when available. I also told him that I’d be open to including a short-written Q&A with Sterer in my post if that’s something he’d like to coordinate. Whittier thanked me for my interest and told me that they’d be happy to send me a copy my way. When I received the copy, I posted a picture of it on my Instagram, Threads, Twitter and Bluesky ahead of its release, which you can also see below.
Whittier also thanked me for asking about a Q&A, but then apologized, as Sterer was currently busy working on future stories and wasn’t able to take on additional opportunities at that time. So, when I finally got around to reading the book, I decided to submit questions to Santoso instead. But then I got an automated email telling me that Whittier was no longer at Simon & Schuster, and to please direct all communications to Publicity Director Alex Kelleher. So, I submitted my questions to Kelleher, who told me that he’d be happy to coordinate the interview with Santoso. He also asked if I have a physical copy of the book, which I confirmed. And I’m happy to report that Santoso got back to me with the following answers!
Q: What first drew you to illustrating The Underwearwolf, and what excited you most about the project?
A: Firstly, The Laugh! I read the manuscript and Laughed Out Loud. I think the first emotion that I get is a great first indication. I also love it when it invokes the feeling of visual, sound, and even smell in my head. They usually change in the process of course, but these were a good foundation when I started. The Underwearwolf manuscript was funny, lively, imaginative, and left room for me to explore the visual possibilities. I just love it.
Q: How did you approach designing the Underwearwolf so he could feel both funny and just a little spooky for young readers?
A: I started designing on a higher spooky level and dialed things down (slowly) to get the right amount of Fun, Spooky, Weird, and Cute. I personally feel this was a better approach than the other way around. How did I know when to stop? This was part of exploring and trusting my instinct. I also let the design rest for a day or two and come back to it with a fresh pair of eyes. I used the hair sticking up feature to add comedic value and a connection between the human and the Underwerewolf version of the boy.
Q: The book has a lot of energetic and chaotic moments. How do you use movement and expressions in your illustrations to bring that humor to life?
A: Movements and expressions of the character are one thing, but I think page layout also plays an important role in this. I made the layout to try and get readers to move at a different pace as they look at the spread and turn over the page. The over-the-top expressions when the boy was in The Underwerewolf version were deliberate to add tension and comedic moments. The important thing is that I always try to match the energy of the illustrations to Gideon’s words. I don’t want the illustrations to overpower the words or vice versa. The book usually feels much better when both illustrations and words are supporting each other.
Q: Were there any particular visual details or scenes in the book that were especially fun or challenging to illustrate?
A: I loved illustrating the part when the boy was in the process of turning into the Underwearwolf, and also the next spread, when he finally turned into a full Underwearwolf. It was FUN but tricky. Trying to find that balance of tension, weird, spooky, and fun was hard. I tried different solutions before arriving at the final one, and I’m pretty happy with where we landed in the end.
Q: How do you balance playful absurdity—like a werewolf powered by underwear—with making the world feel believable and immersive?
A: I tried to remember my experience walking on the street at night and the different feel that I get from experiencing lighting from the moon, buildings, and streetlamps. The moods, colors, temperatures, smells, and sounds. I think bringing these memories somehow into the book helped to bring everything together and make it more believable, even though The Underwearwolf lived in a stylized imaginary world.
But how was the book, anyway? Did it successfully warn me not to put on lycanthropic-ridden pairs of undergarments?
The Review
I have to say, this book was funny and irreverent (in a good way) with a simple yet effective plot. Already, the title page has so much character that describes so much about our main character. Interestingly, he is not given a name, so I’ll just refer to him as “the narrator”. He’s a young boy (who I assume is the same age as the book’s target audience, so let’s say no older than eight) who hilariously enough, is something of an underwear enthusiast (even his curtains are underwear patterned). He stares at the different pairs of underwear he owns hanging on his wall that are coded according to each day of the week while shirtless (and implied to be devoid of clothing completely, with the page cutting off the rest of his body). It’s kind of like Maurice Sendak’s In the Night Kitchen but without the controversy.
On the day of his birthday, the narrator receives a gift from his uncle Larry who sent him the “coolest” pair of underwear he could find. I like the designs of the narrator’s family members (his baby sister is so cute!), with their distinctively cartoony square heads, round eyes and pointy noses. This extends to the rest of Santoso’s art style, creating an atmosphere that’s warm, inviting and just as cartoony, which fits the slightly nonsensical nature of the story. Sterer immediately sets up the underwear’s lycanthropic nature through its wool-like design, which is good foreshadowing. On the Wednesday night the narrator decides to try the new underwear on (you could tell it’s a Wednesday because he’s wearing his Wednesday underwear), he sees a tag that warns him not to wear the underwear under any circumstances during the full moon. I like the use of the typewriter-like text for the message, which indicates the stringent and secretive nature of the warning. And the narrator suggesting that the full moon didn’t look too full was hilarious, and honestly really real, as it can be hard for the average person to determine if the moon is actually full around the middle of the lunar month.
Of course, this leads the narrator to try on the wool underwear. And as would happen to any underwear-loving child who isn’t an aspiring astronomer, he mutates into none other than an underwearwolf, a werewolf that only transforms while wearing the wool underwear. I like the shadow at the bottom right of the transformation spread, which is a nice transition to the big, almost cinematic reveal of the narrator’s underwearwolf form on the next spread. And of course, the term “underwearwolf” is a great portmanteau of “underwear” and “werewolf”. This does present an interesting question, though: where did Uncle Larry even get this pair of wool underwear? He probably didn’t intend for the narrator to turn into a humanoid wolf, and it’s surprising he didn’t at least check the tag. But then again, had he done so, that’s one less picture book to give to all the underwear-loving and werewolf-loving children.
Completely under the moon’s influence, the narrator is compelled to leave his house and run off into the night, causing all kinds of chaos throughout the town. He’s tempted to reverse the transformation by taking off the underwear, but figures that he’d be completely nude in public. That does present another interesting question: is the transformation actually maintained by continuous wear, actually causing him to transform back if he took off the underwear? If not, he’d still have fur, so the nudity might not be an issue, though he’d still have to wait until sunrise to become human again. But if the transformation is maintained by continuous wear, then the nudity would in fact be an issue, and judging from the way the text is framed, it seems to be the latter. Either way, it’s a lose-lose situation for our intrepid hero, and it presents some good tension for the narrator throughout the story.
At one point, the narrator bites a bird feeder in half, and I like the detail of feathers flying before we see an owl flying off in the next image, which is a nice little visual detail that the text doesn’t acknowledge. The narrator then encounters a pack of wolves, whom he is able to become the leader of. They are still confused by the wool underwear, though, to the point that one of the wolves literally turns to the reader in bewilderment as they all howl into the sky in unison with the narrator. It’s easily the best joke in the book, which almost feels like the wolf is letting parents know that he thinks all of this is just as ridiculous as they think it is.
Of course, the sun has to rise eventually. And let’s just say that when all is said and done for the narrator, he’s ready to bask in the return of his freedom in more ways than one, evoking In the Night Kitchen but without the controversy once again. And his attitude towards the wool underwear shifts briefly from the way you might expect, to a way you might not expect that opens the door to future adventures. It’s all very much in the spirit of especially crazy behavior young children can get into, and behavior that can be easy for parents to forget that they may have engaged in when they were kids, which actually fits a werewolf quite nicely.
Ultimately, The Underwearwolf is a silly and irreverent story about the consequences of not listening to instructions and the realities of the raw, unfiltered behavior of early childhood. It shows how there are repercussions for not obeying orders, but also how those repercussions aren’t always devastating, and that sometimes, children can just get really crazy, and that’s not always a bad thing. I think that this book will be loved by young kids who engage in especially crazy behavior and are always tapping into their inner werewolf, who might be surprised to see themselves in the narrator. It could also make parents who try to curb that behavior see it from a different perspective without thinking they have to stop disciplining their children whenever necessary. I wonder if we’ll ever see this boy transform once again or get the story of how Uncle Larry found the wool underwear in the first place. It must be a crazy world for a crazy kid!
So, what did you think of my review? Will you be checking out The Underwearwolf? I will be posting an edited version of my review of the book to my Goodreads shortly. Do you have a children’s book that is about to be released? You can send me an advance reading copy of your book (preferably electronic) for me to leave a review on or after the book’s release date in a future blog post. You can also send me the book’s cover for me to promote it on my Instagram, Threads, Twitter and Bluesky before its release date. Check the Contact page for more information. Be aware that I prefer to review middle grade, traditionally published books and books NOT created using artificial intelligence, and even then, I may not review every book I receive.
Until then, stay enlightened, educated and entertained, folks.
