Salt by Mark Kurlansky

From Bookshop.org: Salt You’ll never look at salt the same way again. The only rock we eat, salt has shaped civilization from the very beginning, and its story is a glittering, often surprising part of the history of humankind. A substance so valuable it served as currency, salt has influenced the establishment of trade routes and cities, provoked and financed wars, secured empires, and inspired revolutions. Populated by colorful characters and filled with an unending series of fascinating details, Salt is a supremely entertaining, multi-layered masterpiece.