You may have heard of him, Edgar Rice Burroughs. What's special about these books is which still have the innocent childish affect children's books have and can also choose this new extra maturity to people.
For this reason, many great child protagonists are orphans that no parent to help them (e.g. http://A1Pay06.com/bbs/board.php?bo_table=free&wr_id=2612907