A new book entitled "When the Rivers Run Dry" argues that the global water shortage is the "defining crisis" of our time. In a revealing Salon book review and interview with the author, Fred Pearce, reveals that while we may save over four gallons of water by turning off the tap when brushing our teeth, it takes 265 gallons to produce a glass of milk and 800 gallons for a hamburger. Most of the water that each one of us uses comes from the water used to irrigate the crops that we consume. Water has thus become a global commodity as water is imported in foodstuffs. Despite these and a long list of other concerns the author is optimistic that given huge inefficiencies in how water is used, that significant progress in water conservation can be made.