This long-awaited textbook provides a unified perspective of a rich and varied field. It recognises that in order to develop strategies for improving the decision-making process one needs to understand how decisions are made in practice and in what ways behaviour differs from guidelines implied by normative theories of choice. It is the interplay between descriptive, normative, and prescriptive analysis that gives this book a special flavour. Using a set of illustrative examples, Decision Sciences synthesises current research about different types of decision making, including individual, group, organisational, and societal. Special attention is given to the linkage between problem finding and problem solving. The principal message emerging from the book is that decision making entails a complex set of processes that need to be understood in order to develop sound prescriptions or policy advice.