Mary Downing Hahn has written multiple classics of children's literature. She managed to do this without writing many books in respectable genres like wartime historicals (STEPPING ON THE CRACKS). In fact her most famous books are ghost stories (WAIT TILL HELEN COMES, TIME FOR ANDREW) and mysteries (THE DEAD MAN IN INDIAN CREEK).
Note: If you didn't know the above books existed, you now do. You have no excuse for leaving them unread.
Despite the fact all of Hahn's books are worth reading, not all of them can win awards. This is the way life works. For instance, LOOK FOR ME BY MOONLIGHT has never won an award. Yet LOOK FOR ME BY MOONLIGHT is due for a comeback, since it was a vampire story for teen girls before vampire stories for teen girls became homogenized and saturated the market.
You can read a lengthy excerpt here, on the Houghton Mifflin site. Cynda and her brother Todd are staying with their father at his inn in the north. There are a variety of guests, but Cynda is drawn to one in particular. They meet in secret, signaling each other through clever use of Scrabble.
Then things go terribly wrong because this is a vampire story. A good vampire story.
This was one of my favorite books in elementary school, and no matter what you think of little kids, I had good taste back then.