This book provides a creative and practical, down to earth perspective on how to tackle the complex planning problems characterised by multiple criteria or measures of performance. The book is intended for all who are interested in the theory and practice of planning, no matter whether the field is economic planning, strategic planning, town planning, ecological planning, energy planning -- or just planning itself as a purposeful activity in social systems. It introduces basic notions of how and why we plan, both as individuals and within the context of an organisation. In particular, it provides guidelines for how to choose between alternative actions so as to obtain the best balance between the multiple criteria we choose to represent our objectives. In so doing it develops an operational framework for planning which integrates the concepts of values, objectives, criteria, preferences, decisions, and conflicts.