Well my favorite authors (sorry I can't choose just one) are:
J.K. Rowling: She is a genius I love the Harry Potter books
I can talk all day about her books
but I will stop here.
Phillipa Gregory: She is awesome I love her. She has written a lot of books about my favorite era, Tudor England
and not to mention one of her books was turned into a movie.
Carolyn Meyer: She was the author that introduced me to Tudor England.
Kit Pearson: First of all, she is Canadian
and she was the author to introduce me to WWII Fiction
Gordon Korman: I love his small books, they are perfect for those days where you want to read, but one that you can read quickly.
Last but not least: Joseph Delaney: The author of the Last Apprentice series (but it's a trilogy at the moment)