This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book introduces several paradigms in relation to food crises, and show their respective contributions and limits. It develops further the relationship between rationality and risks. The book explains the governance of food crises. It aslo explains how, facing an unknown situation after the Fukushima nuclear disaster of 2011, Japanese people modified the way they buy and eat their food. The Fukushima nuclear accident in 2011 and its consequences for food safety, analysed in detail by Augustin-Jean in this volume, were of a different nature. The book provides the behaviour of egg producers in Japan in the face of the risks generated by avian influenza. In China, consumers have experienced the same mistrust about their food industry as their Japanese counterparts did, but this phenomenon started much later.