John Scalzi says listen to your teacher: The Great American Novel is 'To Kill a Mockingbird'

Asking a bunch of literate people about the Great American Novel is an open invitation for us all to show off and make cogent, compelling arguments about the importance of [insert a favorite novel here] in the canon of American literature, regardless of whether anyone outside our small circle of literary compatriots knows of the novel or would agree. As a science fiction and fantasy writer, for example, I can make a pretty good argument for Philip K. Dick's "The Man in the High Castle" or Ray Bradbury's "Fahrenheit 451," or maybe even Mark Helprin's "Winter's Tale," and I might even get a cheering section behind the choice. Ubiquity: It has to be a novel that a relatively large number of Americans have read, and that a large proportion of those who haven't read it know about in other ways (for example, by a popular filmed adaptation). Notability: There has to be a general agreement that the novel is significant -- it has literary quality and/or is part of the cultural landscape in a way that's unquestionable (even if critically assailable). Morality: It needs to address some unique aspect of the American experience, usually either our faults or our aspirations as a nation, with recognizable moral force (not to be confused with a happy ending).