It is one of King's most enduring novels; it's crossed over from just being read by his fans, and become a part of a wider cultural consciousness. There's something universal about it; something that feels like a summation of King's previous work in the horror genre. I've mentioned, in the past, the slur that King created his novels by simply taking things with the potential to be creepy – empty hotels, dogs, disease – and ramping up the horror. For his detractors, It is possibly the most obvious example. But his use of classic horror tropes here was wholly intentional; and, by using them, he created what is likely his scariest novel in the process.

It is intimidatingly huge. Fourteen hundred pages long in my printing (the only bigger novel I own is Infinite Jest), and famously weighing nigh-on four pounds, it's a challenge to hold, let alone read. I don't recall a huge amount about the physical experience of reading most novels. The book is all, for the most part. But I remember reading It in the summer. It is, as has been mentioned before on this very site, a summer novel. I spent a week of the school holidays in Derry, King's fictional Maine town, with my fictional friends in the novel's so-called Losers' Club, during the long summer of 1958. I knew them all: Bill, Bev, Richie, Ben, Mike, Stan and Eddie. We were all roughly the same age, we were all misfits, and all that any of us wanted was to stop being afraid. I had things going on in my own life that I couldn't deal with; their problems were bigger than mine, but I felt that they would have understood me regardless. They would have accepted me.

And then they grew up, and I got to see where they landed. The book is essentially two novels, featuring the same characters during different parts of their lives – teenagers in 1958, and adults in 1985 – as they attempt to deal with their hopes and fears; and with the titular menace. The monsterpresents itself as that which you are most afraid of; it finds your fears, and feasts on them. It's a creature beyond any that King had unleashed before that point, because it represented every evil: all childhood fears manifested.

Of course, the most famous and lasting of those manifestations is Pennywise, the clown that – thanks, in no small part, to Tim Curry's performance in the surprisingly enduring TV movie adaptation – has come to be a face of the novel itself. I'd never been scared of clowns, but something about Pennywise taught me how to be. As the novel goes on, we see it manifest as vampires, werewolves, zombies, witches, a mummy, all classic horror icons; but Pennywise is the one that endures, the creation that is wholly King's. In Time magazine, around the book's release, King stated that his thought had been to "bring on all the monsters one last time … and call it It" . He wanted to sum up all of childhood in those fears, and then cast those fears off; to write a novel about the loss of childhood innocence. Pennywise – an image associated with laughter and innocent joy – was his trump card. Of course, Pennywise isn't the novel's biggest terror. The most prominent notions of fear in the novel come from the Losers' Club themselves: their home lives, the things that have made them pariahs.

I can't read It for pure pleasure now, not really. I'm a different reader, and there are things that I would critique, if I had to: common complaints, about how long the novel is; or about questionable scenes concerning childhood sexuality that shocked me when I was a kid. (One particular scene involving the young Losers' Club taking part in what amounts to an orgy shocks me to this day.)

Looking at it as a writer, it's incredible: a structural marvel, an author at the height of his powers, and he's showing off. Juggling dual narratives, historical interludes, an astonishing number of characters, King somehow makes it all seem effortless. It wasn't, of course – at the end of the novel we are told that it took him four years to write – but it seems to emerged from his imagination fully formed. It's perhaps the best example of King's astonishing skill with focalisation, as well, moving between different character viewpoints. Even after multiple reads over the course of my life – five? six? I can't say for sure – it still wows me.

Connections

This novel sits in the middle of much of King's work: in Derry, the fictional town thatis the setting for so many stories; in The Shining's Dick Halloran, saving Mike Hanlon in the Black Spot fire; in the links with the Dark Tower, especially Stuttering Bill and the Turtle (long story for another time); in Mike Hanlon, popping up in Insomnia; in the mentions of the towns from Children Of The Corn. And, most powerful of all, in 11/22/63: when the time-travelling main character visits Derry and meets Bev and Richie. I felt as he did; travelling back to somewhere that I knew, to meet people that I knew from another time.

There's something else that I think is interesting. King's eldest son, Joe Hill (one of the three kids that It was dedicated to) has recently published an excellent and hugely unsettling novel called NOS-4R2. Just as It was a culmination of King's work in the horror genre, Hill has described NOS-4R2 as his "senior PhD thesis on horror". There's a moment in the book where a map is shown of worlds that we cannot visit through normal means. One of them is Pennywise's Circus. Maybe everything is just on the path of a beam …

Next: King's foray into the traditional fantasy genre, The Eyes Of The Dragon.