Possible Clues:

• Master of irony
• Writer with a twist
• Namesake of an annual short fiction prize
• Writer with an award named for him
• ''Ransom of Red Chief'' writer
• Another American author's way of addressing James
• Writer known for twist endings
• The pen name of the short story writer William Sydney Porter
• Whom a short-story award is named for
• Short-story writer famous for twist endings