The purpose of this short contribution is to provide an overview of our current state of knowledge of Africa's petroleum systems as an introduction to the detailed volume accounts that follow. Toward that end we introduce a set of maps on a supplementary CD compiled by Purdy as part of a confidential report provided to industry subscribers some ten years ago. The maps include subsurface as well as surface structural information but, because of their vintage, have not taken account of more recent information. Nonetheless, the regional geological frame-work apparent on the maps has not changed and, in that sense, the maps are as relevant today as when they were first compiled. Moreover the maps serve as a useful building block on which more recently acquired exploration data can be readily added by others using facilitating computer programs.