The Revnd Thomas Robert Malthus FRS was a clergyman of benign temperament but divisive views on the way the world works. Writing initially in 1798 he has continued to inspire and infuriate ever since, as a shelf of recent books on his work testifies. Setting aside the demographic detail of his argument, among analysts and prophets of progress Malthus is in the pessimistic corner. Provoked into print by the endorsement of perpetual progress promoted by philosophic writers of the late 18th century Enlightenment, Malthus damped those dreams by reminding the world that resources were limited but the capacity of man to increase in numbers is great. That inevitable and perpetual collision, he insisted, would defer the golden age forever ensuring that progress, if any, was slow, painful and finite. Although situated in the mostly agrarian circumstances of the late 18th century his prescription of the power of population to (prevent) progress has obvious resonance for today’s concerns about the limits of growth - now a further source of controversy. And so the debate is given new life. This introduction, published on the eve of its 200th anniversary, presents his last word; the final fully worked out edition of his ‘principle of population’, and comments on its possible implications for contemporary issues.