The Topic Guide reviews approaches taken by mining, oil and gas companies in the measurement and reporting of their social investments. While the intended focus of the guide is to explore the measurement and reporting processes of one particular case study – the Newmont Ahafo Development Foundation (NADeF) – the guide expands beyond this to place the topic within a broader context in order to draw out lessons that are applicable to social investments more generally. Firstly, the case study needs to be understood within the context of current trends andthinking around social investment within the extractives industries. The guide therefore defines key concepts, such as social performance, social investment and the social licence to operate, and outlines how the concepts relate to each other. It also explores how these concepts came about, as well as how they have evolved over time and where the trends seem to indicate they are heading towards. This provides the backdrop for understanding why companies carry out social investments and the implications this has for measurement and reporting.