Book excerpt: ecision making is one of the most important activities in both our profes D sional and our private lives today. The literature on the subject has grown considerably over the last fifty years and it now covers many different approaches to the subject. These approaches range from that of creating a mathematical model of the decision situation under consideration, as in operations research and other forms of mathematical decision analysis, to those that are based on human and organizational behavior. Recently, those working in the field have begun to combine approaches to the study of decision situations that arise in organizations, in our personal lives and in the communities in which we live. This book is an attempt to assist those concerned with decision making to work with this combination of approaches. In the past, decision problems have been considered according to the condi tions under which they arise and to some extent in terms of the approaches available for their resolution. Writers on the subject who are mathematically oriented have devised a method of classifying decisions based on the type of mathematics that they suggest be used in the resolution of the problems. This approach leads to the division of decision situations into the categories of cer tainty, uncertainty, risk and competition. Deterministic models available in oper ations research have then been offered as the means of treating decision situations in the category of certainty.