Although it isn't, strictly speaking, necessary, excellent mystery novels often raise larger questions that go beyhond whodunit. Many of them raise questions of philosophy and ethics that get us thinking about more than whether or not the butler did it. Giving the reader sometihng to think about can make a mystery novel all the more interesting.
Tony Hillerman often raised the question of cultural identity in his Jim Chee and Joe Leaphorn novels. For instance, through the course of Hillerman's novels, Jim Chee has serious relationships with two women who make him question whether he wants to continue living and working among the Navajo, or live in the dominant culture. As Chee struggles with this question, and with the question of whether he wants to continue to study to be a Navajo yataalii, or "singer," readers get the chance to think about what it means to be a member of a culture. We get to think about our own identities.
Robin Cook raises many larger ethical questions in his novels. Througout his novels, Cook has challenged readers to consider the ethics of managed health care, stem cell research, concierge medicine, medical tourism and other very important philosophical and ethical issues in medicine. In fact, Cook addresses these larger issues quite directly at the end of his novels, where he outlines his own position on the issue at hand. Those commentaries (and the novels, of course) give the reader the chance to think about the possibilities and limits of medicine really are.
Other philosophical and moral issues come up frequently in Alexander McCall Smith's The No. 1 Ladies' Detective Agency series. In several of those novels, Mma Ramotswe faces moral and ethical dilemmas. For instance in Tears of the Giraffe, she faces the dilemma of whether to resort to blackmail to get information that she needs. In the end, she decides that finding out what happened to the victim is worth the morally questionable acts of lying and blackmail. For her, giving the victim's mother some peace is of greater value. Her assistant, Mma Makutsi faces a larger moral question, too: how much should she tell her client about his wife's adultery? Throughout this and the other novels in the series, Smith brings up the ethical question of what is the right thing to do, and in the end, peace and stable relationships often are worth the occasional lie, witholding of information, or blackmail.
Agatha Christie often raised larger philosphical questions in her novels. In Ten Little Indians (AKA And Then There Were None), she raises several questions about guilt. Are there degrees of guilt when it comes to killing someone? Are some people more guilty of murder than others? And who should punish those people? Those questions, to me, are as interesting as the plot is. In Evil Under the Sun, Christie addresses the question of whether the desire to kill makes a person as guilty as killing does. In The Mirror Crack'd, Christie invites the reader to think about guilt when actress Marina Rudd encounters Heather Babcock, a devoted fan who accidentally infected Marina with German measles, leaving her unborn child with retardation. Was Babcock guilty? Those are by no means the only novels in which Agatha Christie discusses questions of guilt and innocence, and what counts as murder and what doesn't.
In my own Joel Wiliams series, one of the questions I like to think about is: what are the limits of ambition? How far is a person willing to go to achieve his or her goals? Several of the characters in my novels are ambitious and very goal-oriented. It would seem that they would stop at nothing to "win," whatever winning means to them. I wonder how that kind of ambition affects a person, and what it might do to her or his character. That's why I address that question in my novels. I think readers of mystery novels probably wonder about these larger questions, since they're often behind human behavior- including murder.
What larger questions are in your favorite author's novels?