The Adventures of Huckleberry Finn is a novel by Mark Twain about Huck, a mischievous boy, who runs away from his drunken father. Huck meets up with Jim, a runaway slave and they travel down the Mississippi on a raft. The two escape through various misadventures, including the family feud between the Grangerfofrds and Shepherdsons and the conning "duke and king." Finally, Jim is captured on the Phelps' farm, Huck plans an escape and, finally, it is revealed that Jim is now a freeman and Huck's father has died.
The main protagonist of the novel, the story focuses on Huck's progression into maturity. It is a bildungsroman, or coming of age story, tracking Huck's moral and intellectual education. At the beginning of the novel he is adopted by the widow, who promises to "civilize" him. Her idea of his education involves learning proper table manners, listening to her reading the Bible and going to school regularly. None of these appeal to him, but he obeys in varying degrees, depending on his mood and level of guilt. Huck is a smart, straightforward boy. He has none of the fancy imagination that Tom Sawyer, his best friend has, a fact which sometimes bothers him. He is completely genuine and has none of Tom's self-centeredness. He does not disobey for the sake of disobedience; he does so purely from an inability to follow the rules properly. It is not in his nature, nor his upbringing, to be comfortable in society such as the widow's, and though he tries his best for her sake, he is not always successful. He is not one immediately accept what people tell him as fact; he likes to think things out for himself. He will let matters rest in order to keep the peace, though in the end he will always believe what he wants to believe. This will be an important characteristic as his relationship with Jim progresses over the course of the novel.
He learns to read and write but the religious education that the widow wishes to impart misses its mark, mostly due to the fact that Huck receives conflicting information from her and her sister, Miss Watson. His quick appraisal of the inconsistencies in their teachings leads him to the decision that where matters of morality are concerned, he is probably best left to his own devices. This becomes the nature of his education as a whole, as he escapes from his father's care and strikes out on his own. His journey down the Mississippi River with Jim by his side is his education and Twain would probably argue that the river is a much better teacher than the widow or Miss Watson.
The most important change in Huck's character is his eventual rejection of the institution of slavery. He has grown up in a society which teaches that slaves are sub-human pieces of property to be bought and sold. Huck is not so callous, not wanting to play a trick on Jim, despite Tom's urgings, for example. He does seem to accept the institution as a given; when he finds out that Jim has runaway he immediately assumes that people will call him "a low down Abilitionist" for keeping Jim's secret. Though in the way that he thinks about the problem he sounds like a typical Southerner who believes that slavery is a necessary and acceptable institution, the way that he acts demonstrates his willingness to challenge the system. He has further doubts but he always acts in Jim's favor and in the end his transformation is complete and his thoughts mirror the way that he has always acted. He is able to see that Jim has never acted as an unfeeling, subhuman and in fact has been better to him than most people he has known. The moment is able to see this and work out for himself what he believes is right is when he reaches a new level of maturity.
Miss Watson's slave who runs away and joins Huck on a journey down the river, Jim is the novel's other main protagonist. He has most often been at the center of controversy surrounding the novel, as his portrayal troubles some people. His belief in a prophetic hairball, for example, seems to some people as a character that we are meant to laugh at and make fun of. For example, the illustrations that accompany the story have often played up this comical aspect at Jim's expense. Some illustrators seem to have purposefully chose the scenes which highlight Jim's superstitious nature or circumstances where Jim is in a compromising situation, such as when he is dressed up as a "sick Arab." Being placed in this context makes Jim out to be silly and insignificant, while if the narrative in its entirety is examined, it becomes evident that he is actually the focus of a story that is firmly against slavery as an institution.
Jim is kind and thoughtful and though uneducated, he is knowledgeable in the ways of nature and possesses a good deal of common sense. He is superstitious, but much in the way that Huck is as well. They both agree that bad luck cannot always be avoided but it is a good policy to prevent it when possible. Their belief in something that others might dismiss as foolish is contrasted with the beliefs of the widow and Miss Watson. Jim's superstition is mostly a way to see the difference between the civilization that Huck tries to avoid and the natural world in which he feels most at home. Jim occupies this natural world fully, as he is not allowed into the society which professes its civilization.
Huck and Jim's relationship becomes richer and more binding as they make their way down the river. Though he is not often in a position in which he can do much to help, Jim does all that he can to protect Huck and watch out for his safety. Jim does not change as a character over the course of the novel, rather, his more of his character is uncovered as the novel progresses. For example, in chapter 15, Huck tricks Jim into thinking that he imagined a fog that had separated the two of them. Jim, who had mourned Huck's loss, scolds him for being unfeeling and capitalizing on Jim's sadness. This shows Huck the depth of Jim's concern for him and teaches him to be more thoughtful of his feelings. Later, Jim tells Huck about the time that he struck his daughter for disobedience and then realized that she was deaf. The intensity of his regret for being so unthinking and inconsiderate is a testament to the depth of his feelings for his family and for people in general. It also gives the reader a greater understanding of Jim's reasons for scolding Huck for the trick he played and allows a glimpse of Jim's complexity. Jim is by no means the simplistic buffoon as some might be quick to label him. He is a character with a depth of feeling, experience and compassion and is Twain's major evidence for this narrative's renouncement of slavery.
Tom Sawyer, the subject of the novel to which Huck Finn was meant to be a sequel, serves in this story as a contrast to Huck. He is clever and mischievous, looking to have fun whenever possible, quite often at someone else's expense. When he and Huck come across a sleeping Jim, he is the one who wants to play a trick; Huck is more concerned about the risk of being caught. Huck is an outsider and thus anxious about his interaction with figures of authority, while Tom is confident in his position within his society, and thus feels at liberty to cause trouble when he wishes.
Tom is a voracious reader of adventure and romance novels and the stories act as fodder for his wild imagination, which is the envy of Huck and many of the other boys. At the beginning of the story he gathers the boys together and establishes his own gang, based on his idea of a proper band of robbers. He creates a situation built from a combination of the adventures he has read. His ideas are completely illogical and not completely worked out, yet his popularity leads the boys to join in despite any misgivings as to the reasonableness of his plan. His wild ideas, which prove to be in actuality quite tame in their execution, contrast with Huck's calm, logical thought process. Huck is decidedly more grounded in reality than Tom, yet he ends up having the more dramatic experiences.
Tom is also distinctly more self-centered than Huck. He is motivated by his own desires; he acts purely for his own amusement. This is harmless at the beginning of the novel, as he leads raids on Sunday school picnics. Later, as he concocts a complex plan for freeing Jim, all the while knowing that Jim is already free, he ends up placing himself in danger and receives a bullet in his leg. His reliance on adventure stories is one demonstration Twain's disapproval of the genre and his frustration with the South's love of myths of royalty and gentility. His actions at the Phelpes' farm demonstrate the foolishness that comes from someone devoted to these kinds of romantic stories. Tom represents the South's combination of myth and religion as he scolds Huck for the sin of stealing a watermelon but proceeds to cause incredible discomfort for the Phelpses as well as Jim, all for his own entertainment.