At one time or another, everyone has said "I am thirsty". Yet what causes this sensation of thirst? It is obvious that a certain quantity of fluid must be present for the body to function normally. How does a water deficit in the body then influence drinking habits? But supposing the physiological need is met, what about the psychological need or social need? Water is certainly the most necessary fluid; then why do we humans often prefer other beverages, even at great cost of effort or money or health? The subject of thirst and drinking behavior are uniquely discussed in this book. For the first time both the physiological and the psychological aspects of water and beverage consumption are examined in one volume. The many recent developments concerning how a lack of water is signalled physiologically and processed neurally to affect drinking behavior are critically surveyed. Prospects for understanding the cultural and sensory influences on beverage consumption are mapped out. The thirty-one chapters by authorities in the field were all mutually reviewed and revised in the light of precirculated comments and round-table discussions. Together they provide a complete picture of the current state of knowledge on what determines fluid consumption in human beings and animals.