This book was published following a conference on naturalistic decision making held in Stockholm in 2000. Naturalistic decision making (NDM) is a subset of decision making theory that focuses on situations where there are ill-structured problems; uncertain dynamic environments; shifting, ill-defined, or competing goals; action/ feedback loops; time stress; high stakes; multiple players; and organizational goals and norms. The book updates NDM research originally compiled in the 1993 edited volume by G.A. Klein et al., “Decision Making in Action: Models and Methods”. The 2004 book is organized into three sections: individual decision making, social decision making, and decision making methods. Readings on individual decision making include the second chapter, which describes the mental models that are constructed when decisions are made by “experienced people under complex dynamic and uncertain situations”; the third chapter, which focuses on command control and forest firefighting, and concludes that more information and resources don’t always lead to better decisions; the second and sixth chapters, which discuss situation awareness as a critical element in some types of decision making; and the ninth chapter, which focuses on the role of organizational goals and norms in professional decision making. The social decision making part of the book investigates the social context around professional decision making, and includes chapters on team decision making and shared mental models. In this section, Chapter 14 addresses performance of fire ground commanders; Chapter 17 describes the role of culture in decision making; Chapter 18 analyzes the Challenger disaster from a cultural perspective; and Chapter 19 describes training methods for decision makers coping with ethical problems. Overall, this book reports on a variety of empirical research and theory by NDM researchers. Although NDM is a relatively new field, this book begins to illustrate that naturalistic decision making models are complex and they must account for many interactive influences on decision making.