In The Adventures of Huckleberry Finn, how has Huck changed and grown as a person over the course of the book?

You have asked a very perceptive question, because while
all critics agree that Huck as a character undoubtedly changes, develops and matures
during the middle section of the book, a number of critics argue that the final section
of the book (Chapter 31 to the end) represent a regression of Huck as he becomes, once
again, a mere sidekick to Tom Sawyer's hair-brained schemes and all the interesting
moral development we have observed in the middle section is
lost.

However, Huck's experiences of society and, in
particular, of being 'sivilised' have made him distrustful and suspicious. Therefore, as
he travels down the river with Jim, this forces him to question the things society has
taught him. The major example of this is Huck's relationship with Jim. According to the
law, Jim is the property of Miss Watson, but, to Huck and his sense of logic and
fairness, it just feels 'right' to help Jim. Thus in the middle section of the novel
Huck's natural intelligence and his willingness to persevere and think through a
situation to its logical conclusion leads him to some decisions that are correct in
their natural context, but would shock the society of the time that this novel is set
in. An excellent example of this would be when Huck and Jim encounter a group of
slave-hunters, and Huck discovers the value of a lie - sometimes, because of the
problems in society, lieing is the right course of
action.

Interestingly, because Huck is a child, he looks
upon the world with child-like eyes. All the experiences he encounters provoke deep
thought as he tries to work out what is 'right' and what is 'wrong' and what is just
ridiculous. Huck's willingness to create his own rules in situations is what makes this
novel so fascinating as he confronts society in all its guises and so often finds it
wanting. Yet, as many critics have established, Huck is still part of and a product of
his society, and thus we see him struggling with initial preconceptions regarding blacks
that his society has ingrained in him, and, as already mentioned, at the end of the
novel, he is quick to become a subordinate to Tom Sawyer. Yet for all of these
imperfections, and perhaps because of them, we recognise in Huck a falliable, human boy,
who nevertheless shows himself through the course of the novel to be a thinking, feeling
human being rather than just a product of society.