This book uses risk in its dictionary meaning as the probabiHty of an unde­ sirable outcome, and has two research questions: when managers make de­ cisions, what leads them to choose a risky alternative? and: what deter­ mines whether the decision proves correct? Answers to these questions form a model of decision making that explains the process and results of managers' risk-taking in the real world. There is an extensive literature on risk and decision making because the topic has been of interest in many disciplines since at least the 18subsub century. Thus insights on the research questions are available from studies of ani­ mals, humans and organisations; and have been drawn by scholars in biology, psychology, finance and management. Even so, there is a large gap as most studies are conducted away from corporate settings and use subjects with limited decision experience. The few studies set in real-world conditions tend to concentrate on just a single aspect of decision makers' attrib­ utes, setting and behaviour, and on either decision choices or outcomes. The empirical work in this book is designed to fill part of this gap.