It's been more than a decade since any new Calvin and Hobbes comic strips have appeared, but the fearless and philosophical duo still delight millions of readers. Some are rereading their well-worn collections for the nth time, while others are just discovering the incorrigible twosome. No matter where readers are coming from, the pair's adventures and conversations seem just as genuine today as they did when they were first committed to paper. Yes, the strip's creator, Bill Watterson, was a phenomenal artist (his Martian landscapes, seasonal backdrops and depiction of a T.rex flying a F-14 are all classics) and yes, he was a great writer, but it is the strip's ring of truthfulness that may have been its most attractive quality.

Calvin and Hobbes follows the adventures of the mischievous boy Calvin and his best friend Hobbes, a tiger who may or may not actually exist. Their relationship is by turns playful, combative, thoughtful and fantastical; they act and sound like real best friends. But they do things that most kids can only dream of – they time travel, dig for dinosaur bones in the backyard and build legions of abominable snowmen. Sometimes Watterson sketched out memorable parables that drove their point home with a chuckle (often at Calvin's unwitting expense) and at other times he gave readers straight-up gags, explored family dynamics or sent his intrepid duo hurtling through time and space and over cliffs. No matter what magic Watterson concocted, there was rarely a moment when the strip felt forced or, worse yet, meaningless.

It's pretty mind-blowing to experience something that you expect to be nothing more than ordinary, only to find that it is changing the way you look at the world. (Kind of like stumbling across the Beatles on the radio in 1964 sandwiched between Harry Mancini's Pink Panther theme song and a Jan and Dean tune). Calvin and Hobbes was intended to transcend the funny pages, but no one could have guessed just how far. Watterson knew that his strip allowed him access to his readers' brains for a few moments every morning and he was determined to make the best of it. He didn't see it as a time to deliver clichés, easy gags or sloppy artwork; he saw it as a moment when he might get people to think outside the box, or to rethink how they think inside it. Even though his efforts were often constricted to three black and white panels, Watterson used that space to discuss everything from mortality to the existence of God and the perils of mankind's self-destructive habits. It was always heartening to see a cartoonist discussing issues of such depth with his readers, some of whom were so young that they were learning how to read using the strip or had never thought about what happens when we die.

The strip's authenticity is secured by Watterson's refusal to sell out. He didn't become a cartoonist for the attention, the accolades or the money. He just wanted to create the best comic strip possible. As he once wrote in the introduction to a Krazy Kat collection, "[W]e seem to have forgotten that a comic strip can be something more than a launch pad for a glut of derivative products. When the comic strip is not exploited, the medium can be a vehicle for beautiful artwork and serious, intelligent expression." So, instead of embracing the fame his work afforded him over the years, he gave only a handful of interviews, rarely appeared in public and maintained a very modest lifestyle. He was equally withholding of his creations, whom he never allowed to be merchandised. There were no Hobbes dolls, no Spaceman Spiff action figures and no coffee mugs with Calvin and Hobbes one-liners splashed across them. Considering that all his peers were cashing in on their creations – Charles Schulz (Peanuts) and Jim Davis (Garfield) each earned tens of millions of dollars a year at the height of their fame – it was a tack that was as admirable as it was confounding.

Readers may have never thought about Watterson's personal choices when they read the strip, but that strength of character echoed throughout his work. Calvin and Hobbes is complex, thoughtful and thought provoking. Calvin and Hobbes aren't plastic and one-dimensional, like so many of their contemporaries on the funny pages whose creators strove to make them explicable in a single sentence. Garfield is a fat, lazy cat who loves to eat and give his owner grief. Beetle Bailey is an inept and lazy army private who is forever running afoul of his superiors. That's all you need to know to laugh at either of those characters (and lazy is the operative word here). Now we come to Calvin and Hobbes – a hyper-imaginative kid and his pet tiger who may or may not be real, depending on who's looking at him. But that's just the surface. That doesn't really begin to explain Watterson's unique storytelling device in which readers switch between the world as Calvin sees it – a fantastical place – and as adults see it – a cut 'n' dried conventional reality. You need to immerse yourself in Calvin and Hobbes to truly understand it. Sure, you could read one strip, get the gag and move on with your life, but you'd be missing out.

Calvin and Hobbes may have whisked its readers away to faraway planets, the Mesozoic era and a cubist world, but Watterson was always most concerned with having his richly detailed characters parse real issues. That element of genuineness continues to draw in, engage and hearten readers. We still love Calvin and Hobbes because it manages to make imagination real – and that is a rare thing indeed.