Probably, the most iconic of blockbuster hits based on books, Harry Potter has become a cultural phenomenon. J.K. Rowling sold millions of her series. Then, the movies, all eight, consistently ranked as highest-grossing films worldwide. With all her financial success, Rowling makes sure to give back. She donated proceeds from her later released short books, such as Fantastic Beasts and Where to Find Them, to the charity Comic Relief.