[Public health in the XXI century]

To understand what will happen in the future one must draw on the experience of those from the past who have tried to predict what is happening now. The paper develops a taxonomy of visionaries of futurologist; the advocates of historical determinism, who come from both the left, such as Marx, and the right, such as Toffler and Fukuyama; the scientist, ranging from Leonardo da Vinci to Arthur C. Clarke, and the pragmatists, who seek to learn from evidence and the experience of others. These will be examined in turn and the frequent failings of the first three will be illustrated. Drawing on experience in a variety of European countries it will be concluded that our best hope is to learn from each other and from empirical evidence. The article will conclude with a review of some of the challenges which are either predictable but being ignored or totally unpredictable.