Murray N. Rothbard was an American intellectual, individualist anarchist, author, and economist of the Austrian School who helped define modern libertarianism, and popularized a form of free-market anarchism he termed "anarcho-capitalism". Penning over 20 books and many articles, Rothbard can be considered one of the most influential writers of the Agorist movement, as well as having left a massive impression upon the different branches of the Libertarian ideology.