Like Charlie, Lola and Clarice Bean, their creator, Lauren Child, is funny, whimsical and completely original.
The irrepressible Lola was inspired by a sweet little girl Lauren Child saw once on a train in Denmark. That explains why, in Lauren's mind at least, Charlie and Lola live in an apartment in Copenhagen that features the retro-style Scandinavian design beloved by the author/illustrator. Lauren, one of three girls, says Charlie was partly inspired by her older sister who was "very, very kind and responsible".
Charlie is almost too good to be true as he's forever explaining things to his four-year-old sister and helping her get to grips with life's little problems such as eating tomatoes and starting school.
"You have to remember that we see just a tiny snapshot of their day and we see the best of them," says Lauren.
"It was meant to be about the sibling relationship - that's why you never see the parents. I'm much more interested in how children communicate."
Yet in her latest book, Slightly Invisible, Orchard, $19.99), Charlie is not nearly as good-hearted as usual. He'd like Lola to leave him and Marv alone so they can go looking for strange and tricky creatures. Lola doesn't take kindly to being told to stop bothering him and manages to turn the situation to her advantage.
Lauren, who has no children of her own, says she herself is not at all like Lola but she watches children, listens to their conversations and remembers what it was like to be a child.
"It's about putting yourself in someone else's shoes and remembering back. I think most writers do that. You just need to be able to observe things really well."
Lauren is also a magpie collector of beautiful fabrics, bits of paper and all sorts of things - many of which end up decorating the pages of her books.
She's sold more than 3 million books worldwide so far. It's a far cry from her early career when she drifted from job to job, making no money or headway into finding her niche. Before her first book Clarice Bean - That's Me was published in 1999 she was painting china, trying to set up a lampshade business and working for British enfant terrible artist Damien Hirst.
Lauren Child is now writing about her new favourite heroine, Ruby Redfort. Some children may remember Ruby from the Clarice Bean books (her catchphrase is: "You better believe it, Buster").
Lauren has committed to one Ruby Redfort novel a year (aimed at nine to 13 year olds) but still has plenty more Clarice and Charlie and Lola stories in store. She'd also like to revive That Pesky Rat who wears a distinctive purple Pringle-design jumper.
The award-winning author is now a UNESCO ambassador, visiting Mexico and Mongolia and fundraising and campaigning for impoverished children. Proceeds from That Pesky Rat go to UNESCO. It's a fitting fundraiser, as the street rat is homeless, much like many of the children UNESCO is helping. Part of Lauren's role is raising awareness about children in Mongolia and Mexico but without casting them in the role of victims.
"When we went to Mexico the children didn't want to be seen as victims - they wanted to be seen just as children. They've had a bit of a bad start but there's no reason why things can't change for them."