When a wave of destruction hits, everybody looks for somebody to blame. Alan Greenspan, former chairman of the US Federal Reserve, once lauded as the “maestro”, has, to his discomfort, become the scapegoat. But even though I dare to disagree with him on some points, much of the criticism is highly unfair. Mr Greenspan remains the most successful central banker of modern times. More important, blame distracts from the challenge, which is to understand what happened, why it happened and what we should do.