"The King of Horror" produced his finest tale when he wrote IT. Impressively long at 1000+ pages, King takes his readers on a thrilling joyride back to the wonders and terrors of childhood. Like no other living author, King remembers what childhood consisted of and has the uncanny ability to recall it for us in all its intensity of conflicting emotions.
The plot of this novel is straightforward. Set in 1958, 7 children must face down an almost supernatural evil which they come to call IT. Able to take on the aspect of each person's worst fear, IT mostly sleeps only to awake every 26 or 27 years to feed on the children of Derry. After a series of adventures, the children battle IT to a draw. 27 years later, as adults, they are recalled to Derry to once again do battle with IT's ancient evil.
King interweaves the events of the present day with those of 1958. His characters ring completely true, although they are more vibrant as children than as adults. The various subplots and adventures experienced by the children (the apocalyptic rockfight, dam-building, movie-going, Silver, to name a few) enhance the verisimilitude of the story.
I must caution you on two things. 1st, there is a sex scene late in the book that many will find offensive. While integral to the plot, King could have developed a less viscerally offensive avenue for his characters' escape. It is King in his "if I can't get terror, I'll take horror, and if I can't get that I'll go for the gross-out" mode. 2nd, I am one who equates the name of Stephen King with the term "finest living author". His work, while at times crude, even gross, has the depth and vibrancy of the best of Dickens. No stylist he, but a storyteller without peer with an uncanny ability to delineate character with a few sentences. This is his finest work. Read it.