[3] His 1985 papers (with Jeremy Bulow and John Geanakoplos) developed the concept – and invented the terminology – of "strategic complements" that is now commonly used in game theory, industrial organisation and elsewhere.
[6] His papers (many of which are co-authored with Jeremy Bulow) apply ideas from auction theory to other economic contexts, including finance and political economy.
He was principal auction-theorist designing the UK '3G' mobile-phone license auction that raised £22½ billion in spring 2000 and was far more successful than several parallel exercises on the European continent.
In 2002, he advised the UK government on the world's first auction for greenhouse gas emissions reductions, working with Nobel prizewinner Eric Maskin.
He participated in the meeting that drafted the Potsdam Memorandum to the 2007 UN Climate Change Conference in Bali;[16] he is on the Environmental Economics Academic Panel to the UK's Department of the Environment (Defra).