The Central Karoo is an arid, extensive landscape, experienced by many people as a sanctuary of austere but captivating beauty. At the same time, the people who live in the region are mostly poor - high levels of unemployment and inequality characterise the local economies and social fabric. South Africa is investigating the opportunities for introducing more natural gas into the predominantly coal-dominated energy mix. One option is to exploit naturally occurring methane, liberated from deep shale layers in the Central Karoo through horizontal drilling and hydraulic fracturing technologies (‘fracking’). Very little is known about the distribution and magnitude of the gas resource, or whether it can be extracted at economically viable rates. If shale gas development were found to be economically viable, the economic and energy security opportunities of a medium to large shale gas resource would be substantial; as would be the social and environmental risks associated with a gas industry in the Central Karoo. This has been presented to the public and decision-makers as a stark choice between economic opportunity on the one hand and environmental protection on the other. It has become a highly divisive topic, but one which has been, up to now, poorly informed by publically-available and trusted evidence. To address this lack of critically-evaluated information, a Strategic Environmental Assessment (SEA) for shale gas development was commissioned in 2015 by five national government departments of the Republic of South Africa. Phase 2 of the SEA process was undertaken as an independent ‘scientific assessment’ and is reported in this book. The 18 chapters were drafted by 146 authors and peer reviewed by a further 75 independent experts and also by stakeholders involved in the process. It is the largest scientific assessment ever undertaken in South Africa and has set a national precedent on how strategic issues of great importance and consequence should be dealt with if critical development choices are to be guided by evidence-based policies.