This chapter describes a model of decision making skills under time stress, a training strategy based on that model, and experimental tests of the training strategy. A prime example of the kind of decision making addressed by the model is Naval ship defense against an approaching aircraft whose intent is ambiguous. The Vincennes and Stark incidents are prototypical cases of this kind, illustrating two different ways that such decision making can go wrong. But similar decision making skills are required in many other domains, such as medicine, fire-fighting, commercial airline emergencies, and even chess. In each case, the decision maker must gauge the available time for collecting and analyzing information and must usually act on an incomplete picture of the situation.