Shirley Jackson is by far the best horror writer to be found on your list. Her work includes such classics as THE HAUNTING OF HILL HOUSE and "The Lottery." If literary merit is measured by the influence of an author on future generations of storytellers and by the length of time over which that author's work continues to be read, Jackson is unquestionably one of the "greats" of the genre -- and her work was not limited to horror.