Overview

The development of more efficient means for producing and working with iron, and the production of high-grade iron, is one the key advances in human history. Because iron is harder than bronze—the metal most commonly used before iron—it is better able to hold sharp edges, making it a superb metal for weapons and tools. Armies bearing iron weapons held a significant advantage over forces equipped with bronze weapons. This superiority gave a name to an epoch—the Iron Age—which began in approximately 1000 B.C.

Equally important, but not so keenly appreciated as stronger weapons and tools, were the technological advances required, in turn, to produce better iron. Because pure iron does not occur naturally on earth, the skills required for its extraction from raw...