It's about adventures of boys, boys having the time of their life.
I have to disagree with chatterbox891's and many others' review: this book was captivating. Not as good as Adventures of Huckleberry Finn, yet captivating. Just dissecting the way Tom Sawyer thinks has me amazed. And those who gave reviews with no basis, such as boring, etc. truly didn't give the book a chance from the beginning.
I guess we all have opinions, but this is definitely a book that people should read: it tells about a different life than we live, and is highly underestimated by the teen population.