We'd come to think you'd last for ever, popping up in the morning funnies over the breakfast table as surely as the sun would rise. But while age may not have changed you, it couldn't help catching up with your creator, the inimitably dogged Charles "Sparky" Schulz, who always prided himself on making sure you'd never miss a deadline. A blocked artery, a couple of minor strokes and colon cancer - the sorts of things you have always worried about but never had to contemplate - mean that he's had to stop his ritual of plunging you and your friends into your daily round of disarmingly wry emotional turmoil.
Your last daily appearance will be on 4 January, and the final Sunday version of your strip - the longer, more contemplative sort - will come out in February. After that, there will be nothing more than television specials and the crass merchandising of mugs and T-shirts. Good grief, maybe the world is out to get you after all.
Charlie Brown is, of course, more than just another cartoon character. He's become an icon of American popular culture, with all the confusing, contradictory imperatives of art, commerce, cultishness and social commentary that that epithet implies.
For Americans, he has been a lightning-rod for their phobias, their secret desires and the contemplative need to acknowledge just a little pain behind the relentlessly upbeat facade of the American Dream. For those of us on this side of the Atlantic, he has been our introduction to the very foundation stones of Americana - the world of baseball mitts, root beer, lemonade stalls and psychotherapy; of classroom rivalry, casual cruelty, petty snobbery, delusions of grandeur and sibling betrayal; of snowball fights in the deep Midwestern winter and unrequited puppy love.
Some of the strip's admirers say its longevity is due to its ability to keep up with the times. The roster of characters has been constantly refreshed and updated over the years - notably with the addition of Franklin, the strip's only black character, at the height of the Civil Rights movement in the late 1960s, and the infuriatingly elusive birdie Woodstock within a few weeks of the legendary rock concert in 1969. Hey, there was even a reference to Harry Potter in a recent strip (Sally writing to her favourite book character before being reminded he's fictional and giving up).
But such contemporary touches are really no more than marginalia. In fact, the heart and soul of the Peanuts strip seems forever locked into a 1950s time warp, an era before the present preoccupation with drugs, gun violence, child molesters and the like, a time when language was clean and nihilism was never allowed to go so far that it was not redeemed by an underlying humanity.
Terms such as "blockhead" and Charlie Brown's signature exclamation "good grief" have not been updated from the earliest days of the strip and are unmistakably associated with that time. A large part of Charlie's charm is, in fact, his refusal to grow up and move on. That implausibly circular head, with its anxious quiff of hair and crushed linear smile, the zigzag pattern on his shirt and the fragile, knobbly thinness of his knee joints - these have not changed one iota since the style of the strip was fully evolved in the mid-1950s.
New characters - such as Charlie's sister Sally or Lucy's two brothers, Linus and Rerun - may have made their first appearances as babes-in-arms, but they soon hit a developmental ceiling, settling into some indefinable age of articulate immaturity between the end of their toddler years and the onset of puberty. What started out as a cartoon that poked gentle fun at the mores of the time has thus, inescapably, become something of a nostalgia trip.
That does not mean that they have lost their edge. As Umberto Eco wrote of the strip in 1990 - and Peanuts is the sort of cultural artefact that was virtually born to be written about in an Eco essay - "The poetry of these children is born from the fact that we find in them all the sufferings of adults. These children affect us because in a certain sense they are monsters: they are the monstrous infantile reductions of all the neuroses of a modern citizen of the industrial civilisation...."
Their monstrosity, however, has none of the loud obviousness of a modern offshoot of Peanuts such as the Rugrats. It is all contained in the quietly devastating asides and thoughtless actions of children who believe relentlessly in their own sweet goodness. Lucy may be crabby and mean-spirited, but she takes her own negative characteristics as a kind of worldliness that she then tries to sell on at her five-cent psychiatric stand. Peppermint Patty may be an early incarnation of that familiar American figure, the sports jock, but she also has few illusions about being as thick as two short planks. Snoopy may be forever eluding the control of his master, Charlie Brown, but he considers his exuberant flights of fancy - in meeting the Red Baron in airborne combat, for example - as a sort of generosity of spirit.
At the centre of this universe is Charlie Brown himself, a boy continually tripping himself up with the simple belief that he is, at heart, a loser. As Schulz himself says of him: "It always rains on his parade, his baseball game and his life. He's an inveterate worrier who frets over trifles (but who's to say they're trifles?) ... Other than his knack for putting himself down, there are few sharp edges of wit in his repertoire; usually he's the butt of the joke, not the joker. His friends call him `wishy-washy', but his spirit will never give up in his quest to triumph over adversity."
Like Sisyphus pushing that rock up the hill, he is always racing towards the football in the vain hope that this time, for once, his nemesis Lucy won't swipe it away at the last minute. With the kind of tenacity that might inspire a Kevin Costner sports movie, he persists in flying his kite even though he knows it is going to get caught, as always, in that pesky, kite-eating tree. Like the best romantic dreamers, he never gives up hope that the red-haired girl at school will notice him and return his affections (she never appears in the strip as anything more than a silhouette).
It is impossible, of course, to understand Charlie Brown without first understanding his creator. From the outset, Sparky Schulz - his nickname came from a childhood cartoon favourite, a horse called Sparkplug - maintained a quiet determination to succeed in his dream of authoring a comic strip, even as the signs pointed in other directions. In his first stab at art school, he earned a C+ grade in a class entitled "Drawing of Children". The red-haired girl in his class - yes, she really did exist - refused to look in his direction.
But persistence paid off. Charlie Brown was named for an art school chum, and the first incarnation of his column, known as "L'il Folks", debuted in 1947. The strip was renamed Peanuts at the insistence of the United Features Syndicate in 1960, much to the chagrin of Schulz himself who had settled on "Good Ol' Charlie Brown". (Fate, once again, being against our hero.)
As for Charlie's sensibility, it was all the author's own. "I suppose I've always felt that way: apprehensive, anxious, that sort of thing," Schulz said in a 1989 interview. "I have compared it sometimes to the feeling that you have when you get up on the morning of a funeral."
Some of Schulz's neuroses were meted out to the other characters. Sally's reluctance to go anywhere or stray from her routine, for example, reflects Schulz's own. (He moved from Minnesota to Santa Rosa, an hour north of San Francisco, in 1958 and has scarcely budged since.)
At times, of course, Charlie has seemed in danger of being upstaged altogether, particularly by his beagle scout, Snoopy - based on a Schulz family puppy - who earned cult status with the 1966 Royal Guardsmen hit "Snoopy vs the Red Baron". Charlie may be irrevocably linked with the phrase "good grief", but it is his friend Linus who entered the dictionaries with his "security blanket".
But it is his foibles, and his charming pessimism, that will endure.
"As a youngster, I didn't realise how many Charlie Browns there were in the world," Schulz once said. "I thought I was the only one. Now I realise that Charlie Brown's goofs are familiar to everybody, adults and children alike."