In an interview from 2013 he noted: "On my iPad I think I have 40 or so books now. I recommend a book by a scholar who summarises all these works back to Gibbon's Decline and Fall of the Roman Empire. It's called Immoderate Greatness: Why Civilisations Fail by William Ophuls. And then there's perhaps my favourite book of a more detailed type which is called Dirt: The Erosion of Civilisation (by David R Montgomery). That's a really good read. Then there's Collapse by Jared Diamond, which seems to have done quite well and is reasonable. A lot of details are queried by the experts in the field, but I thought it was fine. Then there are books on peak oil and shortages of raw materials. Books on the whole package of long-term growth on a finite planet, going back to the Limits to Growth and a book by one of the co-authors that looks at the next 40 years. That's called 2052 (by Jorgen Randers). And so on and so forth... One of my new heroes is an economist called Kenneth Boulding."  He is married to Hannelore Grantham.
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