In which book by Mark Twain can we find characters as Widow Douglas, the slave Jim, Aunt Sally and Tom?

Question: In which book by Mark Twain can we find characters as Widow Douglas, the slave Jim, Aunt Sally and Tom?

Answer: Huckleberry Finn.
Huckleberry Finn firstly appeared on the book The Adventures of Tom Sawyer, than Mark Twain made a sequel Adventures of Huckleberry Finn. The characters listed above are all from this latest book.