Markets do not always work well. They need guidance. Seán Harkin, a research scientist turned risk manager, makes the case for a mixed economic system where the role of the state is almost as great as that of the market. ?Feedback?, positive and negative, plays a significant role. Change in the system is either ?driven? by positive feedback, effectively feeding on itself, or ?reversed? by negative feedback. By working out what the concept of feedback has to say, the reader is told, we can determine the correct economic policy. This book is a cogent and persuasive response to the financial crisis. There is much learning in these pages and Harkin?s prose is commendably uncluttered given the subject matter. Its arguments, never lacking enthusiasm, deserve a wide audience. It will be interesting to see how this case against the primacy of classical economic theory impresses on the thinking of government policy makers.