Of the expence of defence': What has changed since adam smith?

This essay selectively reviews the history of economic thought on war and peace, starting with Adam Smith. Today, Smith's trickle of thoughts has become a broad marshland. In this marshland, however, discrete currents are apparent - some stronger, some weaker - which this essay identifies, in rough chronological order, as war, defense, conflict, military, security, and peace economics. As these terms often are used interchangeably, one purpose of the essay is to more clearly delineate these intellectual currents and differentiate them from each other. By building canals in the marshlands as it were, the aim is to help all flows of contributions become stronger.