Nonfiction by Mary Catherine Owen
“1977 film in which Luke Skywalker uses the Force in the struggle between the royal houses of York & Lancaster.”
I know this one. “Before & After” is the category; I do well on these clues anyway, but my obsessive preparation for the Jeopardy! College Championship audition led me to go over all the questions and answers (or rather, answers and questions) of the past five years of championship games. This clue was used in 2004.