A central problem of prescriptive decision making is the mismatch between the elegant formal models of decision theory and the less elegant, informal thinking of decision makers, especially when dealing with ill-structured situations. This problem has been a central concern of the authors and their colleagues over the past two decades. They have wisely (to my mind) realized that any viable solution must be informed by a deep understanding of both the structural properties of alternative formalisms and the cognitive demands that they impose on decision makers. Considering the two in parallel reduces the risk of forcing decision makers to say things and endorse models that they do not really understand. It opens the door for creative solutions, incorporating insights from both decision theory and cognitive psychology. It is this opportunity that the authors have so ably exploited in this important book. Under the pressures of an interview situation, people will often answer a question that is put to them. Thus, they may be willing to provide a decision consultant with probability and utility assessments for all manner of things. However, if they do not fully understand the implications of what they are saying and the use to which it will be put, then they cannot maintain cognitive mastery of the decision models intended to represent their beliefs and interests.