When people – alone or in groups – want to solve problems or improve their situation, they make plans. Horst Rittel studied this process of making plans and developed theories – including his notion of "wicked problems" – that are used in many fields today, from product design, architecture and planning to governmental agencies, business schools and software design. This book collects previously unavailable work of Rittel’s within the framework of a discussion of Rittel’s theories and philosophical influences.