What do you think makes this novel an important record of American culture?

Twain was trying to describe the often cruel and darkly bizzare social norms of the time. This should be enough to put Twain's writings into perspective. Although extremely offensive, words like "nigger" were the norms. Black stereotypes proliferate the book but here Twain is just increasing his level of satire. Twain does this to show how hypocritical slavery was in the South. He also illuminates how black people were treated in wider America, "the land of the free." Twain never lets us forget that at the root of the humor and eccentric characters grows a fear and racism that has shaped much of American history. We can wonder to what extent things have improved today.