Public health was recently described as being 'everywhere and nowhere' (Br. Med.J. 319(7213)(1999)839). This image captures the idea that public health is shaped by a range of social, environmental and physiological influences, and that these are mapped across the activities and practices of a range of players. It also suggests it is difficult to capture the spaces of public health. This paper explores how theoretical and methodological developments in the social sciences, in particular ideas around reflexive modernisation, can help us to read the complex terrain of public health policy and practice, and visualise these spaces more clearly.