All the King's Men
by Robert Penn Warren
Duncan plays a role in the Cass Mastern subplot as Cass's friend. He introduces Cass to drinking and gambling, and, perhaps unwisely, to his wife, Annabelle. It is clear from day one of their friendship that Duncan loves and adores his wife above all else. When Duncan finally discovers that Cass and Annabelle are having an affair, he shoots himself, leaving his wedding ring under his pillow instead of a note.