The book is noted for its colorful description of people and places along the Mississippi River, and its sober and often scathing look at entrenched attitudes, particularly racism. The drifting journey of Huck and his friend Jim, a runaway slave, down the Mississippi River on their raft may be one of the most enduring images of escape and freedom in all of American literature.
The book has been popular with young readers since its publication, and taken as a sequel to the comparatively innocuous The Adventures of Tom Sawyer. It has also been the continued object of study by serious literary critics. Although the Southern society it satirized was already a quarter-century in the past by the time of publication, the book immediately became controversial, and has remained so to this day.(Summary from Wikipedia)