Vita humanior sine sale non quit degere—a civilized life cannot be led without salt. So wrote Pliny the Elder (23–79 AD) in his Natural History, Book 31. Salt is, as many of the authors in this volume stress, an essential element not only for human health, but also for a variety of processes in both domestic and industrial life, most notably the preservation of foodstuffs and the seasoning of food. It is not surprising, therefore, that worldwide, assuring a supply of salt, or access to it, has always been regarded as one of the necessities of life.