Amazon has a fiction category called Crime, Thrillers & Mystery. I can understand why Amazon has lumped these books together because many of them will contain elements of both mystery and thriller. However, I believe there are fundamental differences between a mystery and a thriller and just because a novel can contain elements of both, doesn’t mean that the two things should be conflated.
Essentially, I think, mysteries deal with the why’s and wherefore’s of something that has happened, whereas thrillers deal with what is going to happen. Let me explain what I mean.
For my money, a pure mystery is either a whodunnit or a whydunnit.
In the classic whodunnit a crime (usually a murder) is committed and then the rest of the book is concerned with working out who did it. Now often the death takes place off-stage before the story has even started and the book will typically open with the discovery of the body. This is what happens in The Cuckoo’s Calling by Robert Galbraith, aka J. K. Rowling.
If the writer isn’t careful the rest of the book can become a string of interviews where the Inspector or the Private Detective talks to each of the family members, friends, colleagues and suspects in turn (some of whom will inevitably appear suspicious) and the problem for the reader is in remembering who said what and what information they concealed. That’s why classic crime mysteries can be more like intellectual puzzles than anything that gets the pulse racing. I think the real interest in such books has less to do with the crime or the threat of crime and more to do with the tangled relationships of the characters because it is always in those tangled relationships that the clue to the murder will be found.
In a thriller, on the other hand, the reader usually knows who the bad guy is from the outset. There is no mystery here. A crime may not yet have been committed, but the protagonist is in jeopardy and facing huge threats. The question in the reader’s mind is, can the protagonist outwit the enemy and survive?
In Stephen King’s The Shining all the danger elements are made explicit from the start:
- Jack Torrance is an alcoholic with anger management issues.
- They’re going to get snowed in. A previous caretaker in the same situation went mad, killed his family and committed suicide.
- There’s something dreadful lurking in room 217.
- The boiler will blow up if Jack doesn’t keep the pressure under control.
So the reader is left in no doubt as to what is going to go wrong. There is no mystery here, but there is a tonne of suspense. Knowing all of the above, the reader asks not who? but when are these things going to happen? and how are they going to play out? There is a sense of fatal inevitability here.
So this, I think, is the essential difference between a mystery and a thriller: in a mystery something bad has happened and the question is who did it and why. In a thriller the bad thing is still to happen and the reader waits with bated breath to see the outcome.