Which would be the most appropriate salutation in a formal letter to author Sandra Cisneros? Which would be the most appropriate closing to include in the letter?

Both monsters and heroes have some type of super abilities that not everyone else has. They both have a specific goal set in their minds. The heroes are set to destroy the monsters, therefore they are fighting for well-being of the innocent while the monsters are fighting to destroy the good.
There are a whole lot more but I will stop here.