Suspense

Suspense is sustained uncertainty about an outcome the reader wants, held open long enough that waiting for it becomes the experience of reading.

The novelist Steven James draws the cleanest line between suspense and its neighbour: suspense is I'm afraid to look away, while horror is I'm afraid to look. One pulls the reader forward; the other makes them flinch. Most books want the first.

The engine is doubt. There has to be a real possibility that the character will not manage it — that worried feeling that the job is too hard for them — and a story where success is never in question has no suspense regardless of how much action it contains.

The other half is anticipation, which is why setup and payoff and dramatic irony are the two main generators. Tell the reader what is coming and let them wait for it: they do not start you at the top of the roller coaster, they take you up the hill first. Surprise is the opposite transaction — a large effect, spent instantly.

In revision, suspense problems are usually stakes problems in disguise. Before adding threat, check that the reader knows what is lost if the character fails, because uncertainty about an outcome nobody minds is not suspense. It is just an unanswered question.