It is said that the thing about eating an elephant is that it doesn’t much matter where you start, the important thing is to know that it is indeed an elephant and that you have some sense of its size and shape, where the hard bits and the fleshy bits are. As with elephants, so with public health. The determinants of public health range far and wide, from the environment through culture and behaviour, biology, social and political institutions, and all the settings where we live, love, work, and play. If we are not to be paralysed by the enormity of the challenge, we do need a picture, a map, a sense of the jigsaw. How often have you been told that it is all too big and complex, and that you should focus down on one or two initiatives? In work for public health, there is a major tension between having comprehensive strategies and achieving piecemeal progress in the daily round. Of course we must do both, and if we do not have the big picture how can serendipity favour our prepared mind, how can we be strategically opportunistic when the opportunity presents itself?