Favorite Fantasy/Sci-Fi Books

You've already got the author of the Harry Potter books there. It was J. K. Rowling.

The Lord of the Rings is a single story, not a series. It was published as three books because that's how the publisher wanted it, and it's been made into three movies because there's no way you could get through it all in less than nine hours. But Tolkien thought of it as a single story, not a trilogy.