If economics is a ‘dismal science’, criminology may be considered a hopeful one. Its deepest roots are to be found in the ideas of the Enlightenment, particularly the belief in progress and the improvement of human nature. It probably occurred to very few of those sweating aboard the twelve filthy transports that sailed into Sydney Harbour in January 1788 that they were the first participants in an extraordinary social experiment in which viciousness, legal principle and mercy were to be held in constant tension.