Just as significantly, salt has shaped the history of foods like cheese, sauerkraut, olives, and more, and Kurlansky, an award-winning food writer, conveys how they have in turn molded civilization and eating habits the world over. Salt's ability to preserve and to sustain life has made it a metaphorical symbol in all religions. Few endeavors have inspired more ingenuity than salt making, from the natural gas furnaces of ancient China to the drilling techniques that led to the age of petroleum, and salt revenues have funded some of the greatest public works in history, including the Erie Canal, and even cities (Syracuse, New York). The story of salt encompasses fields as disparate as engineering, religion, and food, all of which Kurlansky richly explores. Salt taxes secured empires across Europe and Asia and have also inspired revolution (Gandhi's salt march in 1930 began the overthrow of British rule in India) indeed, salt has been central to the age-old debate about the rights of government to tax and control economies. Because of its worth, salt has provoked and financed some wars, and been a strategic element in others, such as the American Revolution and the Civil War. Demand for salt established the earliest trade routes, across unknown oceans and the remotest of deserts: the city of Jericho was founded almost 10,000 years ago as a salt trading center.

Salt has often been considered so valuable that it served as currency, and it is still exchanged as such in places today. Until about 100 years ago, when modern chemistry and geology revealed how prevalent it is, salt was one of the most sought-after commodities, and no wonder, for without it humans and animals could not live.

Its story is a glittering, often surprising part of the history of mankind. However, as Mark Kurlansky so brilliantly relates in his world-encompassing new book, saltthe only rock we eathas shaped civilization from the very beginning.

Today we take salt for granted, a common, inexpensive substance that seasons food or clears ice from roads, a word used casually in expressions ('salt of the earth,' take it with a grain of salt') without appreciating their deeper meaning. Plato described it as especially dear to the gods.

Cod by mark kurlansky