Klein presents observations of humans acting under real-life constraints such as time pressure, high stakes outcomes, high-levels of personal responsibility, limited information, changing goals, and shifting conditions. Klein studies decision making in the field—observing firefighters, intensive-care units, and chess games—to learn how people make choices when faced with constraints and difficult situations. Klein’s book presents an overview of the research approach of naturalistic decision making and expands our knowledge of the strengths people bring to difficult tasks. Naturalistic decision making is based on the idea that all humans have the capacity to develop, through experience, the skill sets experts call upon to make good decisions. According to Klein, decision making favors both the experience of the decision maker and the context in which the decision making process is meaningful. A new context can change the way that decisions are made, so it is important to understand all characteristics that make the context unique, such as time pressure or limited information.