Prior to the 1990s, most ecological theory viewed predator–prey interactions from the simple perspective of predators consuming their prey. In recent decades, ecologists have amassed evidence showing that prey respond to the threat of predation by changing their behaviors, morphologies, and life histories. These non-consumptive effects (NCEs) of predators may act in concert with the direct consumption of prey to influence prey abundance and community dynamics. Yet, we have only scratched the surface of this active and fascinating field. Despite all the excellent research in this area, some significant questions remain unanswered, including: “How important are NCEs relative to consumptive effects in predator– prey interactions?”; “How are properties of predators used by prey to encode threat?”; and “How does the environment affect predator detection and subsequent NCEs”?. My students and I have used experimental approaches in the lab and field to assess the potential for strong NCEs in the rocky intertidal zone and what factors or environments produce strong versus weak NCEs.