Introduction The food crisis of 2007 and 2008 brought the global problem of hunger and malnutrition to an unprecedented level of concern. While the records of Food and Agriculture Organization (FAO) of the United Nations indicated that 963 million people suffered from hunger, the explosion of food prices gave way to a scenario that nobody had predicted. Rice prices quadrupled and corn prices tripled in very few months (FAO 2009), putting food importing countries under enormous strain to avoid passing those price surges on to the poorest and most needy. FAO’s revised records indicate that another 100 million people swelled the count of starving human beings resulting from the food crises. Most future scenarios are not optimistic (Kuylenstierna et al. 2008; Falkenmark and Rockström, Chapter 6, this volume), especially if climate change projections and future food needs are jointly analyzed (Hoff et al. 2010). The challenge of feeding the world in the cheapest and most sustainable ways is now a top global priority. In many countries, per capita food production has diminished during the last three decades, even though hunger and malnutrition was clearly diagnosed in the 1960s. But while the strategies are numerous and diverse, progress in solving these global problems is too parsimonious. Agriculture production is also threatened by increased insecurity of ample, affordable water supplies of acceptable quality. Global commitment to environmental sustainability implies limits to the extent to which new sources of water can be developed through the construction of dams, reservoirs, and diversions. Agriculture is increasingly outbid in the quest for water by producers of exotic energy like biofuels and tar sands that use and sometimes pollute large quantities. Growing urban demands for water and land are an additional burden upon agriculture. This book addresses the world’s demand for water from a triple perspective. First, it examines the world’s food production systems – from the biophysical and engineering scale, all the way up to the global level. Second, the book looks at the contexts of developed and developing countries and, finally, it analyzes the political and institutional arrangements at national, regional and global levels. In this chapter, we summarize and highlight the most outstanding messages. The ideas are organized in parallel with the volume’s parts and chapters.