Huck Finn has been called the "quintessential American novel." Ernest Hemingway said, "All modern American literature comes from one book by Mark Twain called Huckleberry Finn." I think Huck Finn speaks to us as Americans because the overriding theme is "freedom," which is the idea America was founded on. The book also takes place in the heart of America, the midwest, and takes a journey down America's artery, that famous river, the Mississippi, which runs right through this country and is so important to us. Huck is just a kid, an American boy who is scruffy and uneducated, but he has a mind of his own, and values friendship and humanity, no matter what the price. Huck fights for what he feels is right in his heart, which is what any person, can hope to do. We are proud of Huck because he conquers the odds. He fights a social system, the institution of slavery, racism, and even physical and emotional hurdles in order to help a friend. Mark Twain, in my mind, is America. He writes about American truths and values, he sets many of his stories in the backwoods towns and villages during a time when America was really coming into it's own, around the Industrial Revolution and the turn of the 20th century. As a work, Huck Finn symbolizes freedom and friendship, two strong American values.
The book, The Adventures of Tom Sawyer, is an American classic, which means that the book does reflect American culture and tradition in many ways.
First, what drives the book is Tom's sense of adventure. This maps nicely onto the American spirit, which is characterized by pioneering new places and seeking new experiences - in short, a desire for adventure.
Second, the book is also focused on religion. The church and the social customs and morality that come from the church are all over the book. This is an important point to keep in mind, because it is arguable that Christianity shaped American culture more than any other force.
Finally, this might be a subtle point but Tom is a good business person. He know how to trade things for what he wants. In a sense, we see a microcosm of capitalism.
The religious revival that Huck attends is a part of American culture that continues to have an impact. These revivals of the 19th century were Protestant revivals focused on personal salvation. This, generally, continues to describe a significant portion of American's relgious experiences. A number of conclusions might be drawn from this fact, but the fact itself serves to form a connection between Huck and Americans of today.
I think we would all like to believe we would do the right thing, if given the chance. Most of us think that in Huck's situation, we would be on Jim's side. We would know that slavery is wrong, and we would work to save Jim. We would like to think that.
Huck voices the moral opposition to prejudice and racism that polite Southern society in the 19th century would not speak publicly. He also sticks a pin in the bubble of ridiculousness of such charlatans as the King and the Duke. His bewildered admiration of the gaudy decor of the family's home when he meets the Grangerfords is nothing short of hilarious, and any reader can think of real-life examples of such pretension. Huck's honest, naive assessment of organized religion offers incisive critique of social acceptability and mores.
Huck Finn voices the American spirit versus the European spirit as represented by Tom Sawyer. The physical and mental restlessness of the American spirit, as represented by Huck, and the temporary nature of many of his adventures are largely due to the character of the exploration and development of this continent which parallels the development of Huck Finn (and his explorative exploits.) It is in stark contrast to the romantic version of Tom's life diametrically opposed to the grim realities that European Romanticism brought to the early Americans.
It is in the face of this assault of Europeanism through the Walter Scott, the King and Duke, stories of the Dauphin, almost endless references to European novels "read" by Tom, etc., that Huck stands up and faces his uncertain future, which was America at this time. Nothing was more uncertain after the Civil War.
Huck not only voices the American spirit, but contains the essential American qualities: a sense of liberty, a passion for freedom, a desire for exploration, rational thought and inquisitiveness--which gets him out of many jams and entanglements, a boldness for action, and the quest for adventure.