The bestselling author Louise Penny is a prolific writer of mysteries and thrillers — but for her latest book, she decided to bring a partner into the fold, a novice to the world of mystery-writing: former Secretary of State Hillary Clinton. Their book, State of Terror, brings readers into a world in which a president picks a former rival to be his secretary of state (sound familiar?) — and she must then contend with what Clinton calls one of her greatest fears: nuclear-armed terrorists. In this interview, Penny and Clinton discuss the messages they hope readers take away from the book.