Nomadic conquests have helped shape world history, yet we know little about why they occurred. Using a unique climate and dynastic data set from historical China dating from 221 BCE, this study finds that the likelihood of nomadic conquest increases with less rainfall proxied by drought disasters, which drove pastoral nomads to attack agrarian Chinese for survival. Moreover, consistent with the…

In The Government Machine, Jon Agar traces the mechanization of government work in the United Kingdom from the nineteenth to the early twenty-first century. He argues that this transformation has been tied to the rise of expert movements, groups whose authority has rested on their expertise. The deployment of machines was an attempt to gain control over state action -- a revolutionary move. Aga…