Bradbury readily admits that he has always loved carnivals, magicians, mind readers, and skeletons. Once, as a lad, he was so enthralled by a red and yellow circus banner that he fell down a window pit, shattered one of the glass panes, and crashed into a cellar barbershop. Undaunted, though, he returned to re-observe the circus banner which, for him, in spite of his catastrophe, had lost none of its excitement. Something Wicked This Way Comes evolved as a direct result of this fondness for carnivals. Here, all of his imaginative powers are unleashed to produce an eerie, even nightmarish, novel in which the powers of evil are made manifest through the arrival of the Cooger and Dark Carnival in Green Town, Illinois. This novel is Bradbury's most extensive treatment of the reality of evil. It analyzes the varied ways that evil can be a temptation to man, and it is the most heavily allegorical novel which he has written thus far. Bradbury referred to this novel as his favorite book, his most "delicious" book. He confessed that he wrote it hoping that everyone who read it would do so with a flashlight under the covers, late at night.
The central characters of the novel are two boys, Will Halloway and Jim Nightshade, and Will's father, Charles Halloway. Mr. Halloway is the person through which Bradbury expresses his philosophy concerning good and evil. The theme that emerges in this novel, as well as in several of Bradbury's other works, is that light is good and dark is evil. Bradbury's carnival is the epitome of this darkness. It is the "something wicked" that "this way comes."