After just five years making picture books, Mo Willems has already won four major American book awards. Although readers of all ages certainly appreciate Willems’ unique brand of wacky humour, his characters don’t see what’s so funny.

‘They’re angry. They live in tragedies,’ he says. ‘Don’t Let the Pigeon Drive the Bus is a terrible tragedy. If you were to find the Pigeon and say “I just read this book about you and I laughed”, it would just make it even worse for him.’

‘I think that everybody to a certain degree is frustrated by their existence, no matter how lucky they are. I must be one of the luckiest people in the history of humanity and I’m still a manic-depressive!

'Kids have it worse than adults. There are some very fundamental things: all the furniture in this room was built to my scale. I don’t have to climb up to anything; I’m not going to bust my chin on the table.

'I don’t have to ask permission to go to the bathroom. It’s terribly frustrating being a kid. It’s a terrible time, even if it’s a good childhood, even if you’re loved. It’s difficult. So why not laugh at people who have it worse than you? It is an extension of empathy.’

"So why not laugh at people who have it worse than you? It is an extension of empathy"

The anxiety and anguish suffered by his characters is reminiscent of those in Charles M. Schulz’s Peanuts comic strip, so it is unsurprising that Schulz has always been Willems’ hero. ‘Charlie Brown was the only form of culture that a child could consume that didn’t star a blissfully happy character, and that was just shattering for me, and why my heart is there.’

As a child, Willems enjoyed drawing the Peanuts characters. Now he ensures that his own cartoons are simple enough to be copied by young readers.

‘I don’t believe that books should be read, I believe they should be played,’ he explains. ‘And one way to play them is to draw them. All my lead characters are retrofitted to be as fundamental as possible.’

Another way readers can ‘play’ the books is by interacting with the characters.The eponymous hero of Don’t Let the Pigeon Drive the Bus, The Pigeon Finds a Hot Dog, Don’t Let the Pigeon Stay Up Late and now The Pigeon Wants a Puppy addresses child readers directly; the idea is that they will answer him.

Even by the age of just three or four, through, the conventions of reading are so ingrained that many are unsure how, or whether, to respond to the bird’s entreaties.

Willems welcomes children’s different reactions as part of their individual response to a book. ‘Sometimes children don’t know that they are allowed to yell back at it.That happens. Other times, when the Pigeon says, “Hey, can I drive the bus?”, they say “Okay.” Some kids really like it. They reassure the Pigeon for the rest of the book. They go: “Really, no, it’s fine. Don’t sweat it.”

The Pigeon books and the standalone title Leonardo the Terrible Monster are printed on matte paper in muted neutrals and pastels.

‘They’re matte because it feels right. It’s less intimidating, it’s more handmade, it’s more wearable in a certain way; it’s less formal. So I think that that opens the book up.

'Originally all the characters in Leonardo were all black outline, but it was just too harsh. Part of it was that Leonardo needs to be fading into the background; he’s such a subdued character that he can’t even pop out of the book.

"The text is illustration; the illustration is text."

'So the colour, the tint of brown, that’s another level of experimentation. The Pigeon is a similar palette as Leonardo. I’m using colour as an emotional keystone. The lettering is based on a courier typeset, but everything is done by hand so that you get the emotions right. The text is illustration; the illustration is text.’

Although the tonal palette and mood of Leonardo is similar to that of the Pigeon books, it looks very different, not least because it is so tall.

The lettering is ornate and Victorian in style, the cover announcing “Your Pal Mo Willems Presents”, as though the author is a theatrical impresario unveiling his latest show. ‘I see it as a very stagey book, and so it’s vaudevillian,’ says Willems.

‘The end papers are important to me, and the end papers in this book are the darkness in the theatre before the lights go on. So it’s that sort of hush, and then suddenly you turn the page and, boom – there’s the title card.

'So it’s a very slapsticky, vaudevillian kind of show. The size is important because I never wanted to have to say that Leonardo was small and inconsequential. I want the book to tell it. So I wanted to get the largest production book that I could get so that it would sit on a child’s lap and the character would be to scale and that contrast would heighten the reality of Leonardo’s predicament and Sam’s smallness.’

Among Willems’ latest UK publications is Knuffle Bunny Too, which, like its predecessor, Knuffle Bunny, won a Caldecott Honor Award in the United States.

In the new book, Trixie brings her beloved stuffed toy along on her first day of preschool, only to find that another child has a Knuffle Bunny too.

The rabbits are mixed up, and it takes a dead-of-night rendezvous at a deserted Brooklyn monument before the girls get their own bunnies back. The images of the haggard dads the next morning are priceless.

‘Part of these books, I’m realising now, are sort of what I wish I could be as a dad. I know that if my kid woke me at 2.30am and said, “We’ve got to get this doll,” I would have said “Go back to bed”, but then look at the adventure I would have missed.

'Look at this great moment that would be gone. I like that the dad in this book is willing to do crazy stuff. He tries to get out of it, the cards are stacked against him, but once he does it, he commits.’

Willems’ only books with background images, Knuffle Bunny and its sequel are printed on glossy paper, with cartoons superimposed on black and white photographs of Willems’ neighbourhood.

‘The point of doing the photographs is that kids hate drawing backgrounds and they love looking at photos, so it allows them to draw themselves on top of their location.’

Willems airbrushed out the bins and graffiti, and although the resulting images don’t look quite like the real Park Slope, that wasn’t the intention.

‘They are emotionally true. They’re memoirs. They’re very small stories, and I think it’s important to realise that small stories are still worthwhile. The story is: girl loses bunny, girl finds bunny, the end. Often they say that huge events have to happen. They don’t have to happen. Very small, little things can be important.’

"They’re very small stories, and I think it’s important to realise that small stories are still worthwhile."

The prolific picture book maker is also in the midst of a new series for early readers about Elephant and Piggie. He has already written ten books about the friends; the first four have just been published here. As Willems’ daughter, the real Trixie, started learning to read, he realised that there weren’t many funny books for her reading level. He found sticking to a limit of forty to fifty different words per book a challenge, but one that he enjoyed. ‘It was really fun, looking up the grade level of each word. I think there are two or three bisyllabic words, but it’s mostly monosyllabic. They are fun to make, and that, now, is just how they speak, so it’s not a question of how they’re read, it’s how the characters speak.

They speak in those very simple cadences. Willems won the Theodore Seuss Geisel Award for books for beginning readers with There’s a Bird on Your Head, from the Elephant and Piggie series.

‘I had to write an acceptance speech for the Geisel award and I did it as an early reading speech, so the speech could be read by a four-year-old. That was harder in some ways than writing an Elephant and Piggie book because I didn’t have a character to hang it on.’

Because Willems created Elephant and Piggie as a series he spent time developing the characters before working on the individual stories.

‘I was drawing elephants for three years before I did the Elephant and Piggie books: elephants in suits, elephants with weird sidekicks. And when I drew Piggie it came almost immediately. Even though they’re longer books, and they’re more complex – they’re 64 pages instead of 32 – they go quicker because I love the characters. I love to draw these guys.’

The Knuffle Bunny books were also intended to be a series – in this case a trilogy - but the future of the Pigeon, he says, is out of his hands.

‘It became fairly obvious early on that I would make more than one Pigeon book. I started making The Pigeon Finds a Hot Dog before the first one came out, but I don’t know what’s going to happen to the Pigeon. It’s not up to me.

'That’s the Pigeon’s decision. He’s the one of my creations that I have no control over. Whatever he says, goes.’