Mark Kurlansky's book Salt, which was published in 2002, is a detailed history of salt and its place in both ancient and modern civilizations. In Kurlansky's words, salt—the only rock humans eat—has "shaped civilization."

Although salt is widely available now, in many societies it was once so prized that it was as valuable—if not more so—than currency. Kurlansky explains that Jericho, in what is now the West Bank, was established as a trading post for salt almost ten thousand years ago. Salt was also pivotal to the early Chinese. In 250 BCE, Li Bing realized—through analysis of salt mining in "brine wells"—that underground natural gas can be used to provide power. As a result, he was able to use natural gas furnaces to build the world's first dam. Kurlansky further argues that salt has been a factor in several wars, including the American Revolution, which he argues was at least partially provoked by salt shortages. In addition, salt taxes are what finally galvanized Gandhi to begin his campaign to abolish British rule in India.

Kurlansky also analyzes how salt has changed our diets and shaped eating habits around the world. Many foods—including soy sauce, olives, and cheese—would not be possible to manufacture without salt. Kurlansky explains how crucial salt is to humans, noting that salt appears in nearly every part of the human body, including sweat and tears. In short, people cannot live without salt, because sodium is essential for the body to work properly. There are health implications, though, in consuming too much salt: Kurlansky explores these and notes that modern Americans eat much more than their European counterparts. Of course, he cautions, it is also dangerous to consume too little salt.

Finally, the irony that we have such a glut of salt in the modern world that we use it to liberally salt our snowy streets in the wintertime is not lost on Kurlansky—particularly given its scarcity and value during much of human history.