In a book on African paleoecology and human evolution, it is important to define several key themes, including biomes, vegetation formations and associations, as well as plant physiognomy. We first define these terms, before examining the sources of data employed in paleoenvironmental reconstructions. Finally, we provide an overview of the approaches used to understand past habitats, which underpin the chapters on the specific sites which make use of these approaches to refine our understanding of African paleoenvironments and the place of hominins within them.