The economist Jeffrey Sachs is famed for his work on globalisation and its impact on developing world economies. Previous works have focused on Africa and South America.
But now he's training his eyes on his own country - the United States - and its troubled economy. And what he sees is a moral crisis as much as an economic one.
He came into our studio this week and explained to Guardian columnist Madeleine Bunting the thinking behind his latest book The Price of Civilisation: Economics and Ethics after the Fall.
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(And you can hear our regular podcast from this week here.
