The form of 'reflexivity' - defined by the dictionary as that which is 'directed back upon itself' - that is most relevant to economic methodology is that where observation of the economy leads to ideas that change behavior, which in turn changes (is directed back upon) the economy itself. This book discusses George Soros' ideas about reflexivity and his argument that reflexivity has been neglected in mainstream theorizing, and that this neglect can be held responsible for the failure of economists to predict, explain, or offer a solution for events such as the recent financial crisis. This book was originally published as a special issue of The Journal of Economic Methodology.