"Six years after the Crisis and the recovery is still anaemic despite years of zero interest rates. Is ‘secular stagnation’ to blame? This column introduces an eBook that gathers the views of leading economists including Summers, Krugman, Gordon, Blanchard, Koo, Eichengreen, Caballero, Glaeser, and a dozen others. It is too early to tell whether secular stagnation is really secular, but if it is, current policy tools will be obsolete. Policymakers should start thinking about potential solutions."