How to spend $50 billion to make the world a better place

Bj¿rn Lomborg (ed), Cambridge University Press, paperback, 183 pages, £9.99

In 2004, Lomborg (renowned as author of The skeptical environmentalist) gathered a bunch of prominent economists to assess which measures for tackling global problems would offer the best value for money. But this potentially interesting exercise was fatally flawed by both the choice of economists and the restrictions placed on their purely financial analysis.

The result, written up here, is deeply frustrating. Multi-trillion-dollar estimates of costs and benefits are bandied about with little explanation of how they are derived, and political realities are ignored.

Measures to tackle climate change are dismissed. Two contributors even claim that a 2.5¡C increase in temperature would be beneficial.

Tackling HIV/AIDS comes out top of the economists' wish list - an admirable aim, but you won't find any realistic idea of how it can be achieved here.