Hemingway said all modern American literature comes from this one book, and the claim has held up. Twain handed the novel over to a poor, unschooled boy's voice and let the American vernacular carry the whole thing, dialect and all, which no serious writer had dared before 1884. Underneath the river idyll runs a furious account of slavery and the lies a society tells itself, climaxing when Huck decides he'd rather go to hell than betray a friend. It has been banned, taught, and argued over ever since, and the arguments are the point.

The case for it, the case against, and the rest of the canon open with Pro.