Credited with both unifying China and tormenting its citizenry, Qin Shi Huangdi, the "first emperor of China," is one of the most controversial leaders in the nation's history. His reign brought advances such as standardized currencies, weights, and measures, unified written and spoken language and transportation systems. In battle, too, he was centuries ahead of his time, creating assembly lines to mass-produce precision-crafted swords, arrows and...