Kurt Vonnegut said that a reviewer who attacks a novel is like someone who puts on full armor to attack a hot fudge sundae. I agree with that sentiment. But I also think some hot fudge sundaes are more satisfying than others.

When is a novel extra delicious? To me, it’s when I can sink my teeth into the novel – or when a novel sinks its teeth into me. I think the best fiction is vampiric. It feeds off of the reader, and the reader feeds off of the fiction.

Let’s look at what makes a thriller full-blooded and thick, something that rewards the time invested in reading it.

The main feature of a ‘thick thriller’ is that it provokes thought without demanding conclusions. Keats called this ‘negative capability.’ Take Clarice’s relationship with Lecter in The Silence of the Lambs. What price is worth paying for the lambs’ silence? Is she justified in dealing with one monster to catch another? The book does not force you to choose.

Speculation gets the job done too. Real speculation, not some hokey science where suddenly someone’s a perfect telepath or a ‘scientist’ invents a way to freeze time. Take Daniel Suarez’s titular Daemon. How close is that to happening? Would society splinter in the way he envisions? The novel places itself on the razor’s edge and explores how the things would fall.

Two more: character and moral choices. A moral choice doesn’t have to imply ambiguity. But something with a real moral choice gives the reader some brain food. Ditto for characters. A book that provides insight into human character gains an extra layer that thinner books lack. One way to do this is to double your characters: make the bad guy and the good guy mirror images of each other in many respects, doubles for each other, so that when they do turn out differently, the character reasons are highlighted. Tom Riddle and the Boy Who Lived are doubles for each other. So are Tyler and the Fight Club narrator, or Jekyll and Hyde.

And there’s always plain old cleverness. Give me a bon mot, a fresh spin on an old image, a wise observation about the state of the world. I’m easy. It’s a hot fudge sundae, for goodness sakes!

Just don’t make it so thin that it tastes like paper. I want a book that I can savor, that I can look at closely and find ever finer details to treasure.