We make decisions, and these decisions make us and our organisations. And in theory, decision-making should be easy: a problem is identified, the decision-makers generate solutions, and choose the optimal one, and powerful mathematical tools are available to facilitate the task. Yet if it is all so simple why do organisations, both private and public sector, keep making mistakes, the results of which are borne by shareholders, employees, taxpayers and ultimately society at large? This guide to decision making, by leading decision science academic Helga Drummond, aims to improve decision-making in organisations. It explores how and why decisions go awry in the first place, and offers practical advice on what decision-makers can do to counter the psychological, social and other forces that can undermine individual judgment and pull organisations off course. Full of examples of good and bad decision-making from around the world, it will make readers think more clearly about decisions big and small.