The ways in which the great plagues of the past and present have spread around the world remains only partly understood. Peter Haggett's research over the last thirty years has focused on mapping and modelling the paths by which epidemics spread through human communities. In 1998 this led to him being invited to give the inaugural lectures in a new series, the Clarendon Lectures in Geography and Environmental Studies. The resulting book, Geographical Structure of Epidemics, presents an accessible, concise, and well illustrated account of how environmental and geographical concepts can be used to enhance our knowledge of the origins and progress of epidemics, and sometimes to slow to slow or halt their spread.