Thomas Malthus was one of the three founders of moderneconomics, alongside Adam Smith and David Ricardo. Hewas also the founder of modern demography (populationstudies). In his Essay on the Principle of Population (1798), turned into a greatly expanded and in many ways differentbook in the second edition of 1803, Malthus laid out hisfamous laws of population, later amended to tendencies.The influence of this book has been immense, not merelyon theoretical discussions in economics and the socialsciences, but also in the practical legislation of the earlynineteenth century and the policies of those who ruled theBritish Empire. His theories also provided the key to theidea of natural selection for both Alfred Russell Wallaceand Charles Darwin.Alan Macfarlane, F.B.A., is an Emeritus Professor ofAnthropology at Cambridge University and a Life Fellowof King's College. His website is alanmacfarlane.com