Humanity is facing an existential threat as the impacts of its activities exceed planetary boundaries. Modern industrialised food systems are major contributors to this threat through their profligate use of finite resources, including land, energy and freshwater and degradative impacts on the environment, including greenhouse gas emission, biodiversity loss and food waste. Modern industrialised food systems are also associated with poor public health outcomes. Healthy and sustainable food systems are prerequisites for human existence. The body of evidence associated with the challenges to healthy and sustainable food systems is growing rapidly. A sustainable food system is one that “delivers food security and nutrition for all in such a way that the economic, social and environmental bases to generate food security and nutrition for future generations are not compromised. The chapter also presents an overview of the key concepts discussed in this book.