Lysander Spooner (1808–1887) is the American individualist anarchist and legal theorist known mainly for setting up a commercial post office in competition with the government and thereby being shut down. But he was also the author of some of the most radical political and economic writings of the 19th century, and continues to have a huge influence on libertarian thinkers today. He was a dedicated opponent of slavery in all its forms — even advocating guerrilla war to stop it — but also a dedicated opponent of the federal invasion of the South and its postwar reconstruction. See Let's Abolish Government, a collection selected personally by Murray Rothbard as Spooner's best work.
Ludwig von Mises: "In Nature too, much may exist that we do not like. But we cannot change the essential character of natural events. If, for example, someone thinks — and there are some who have maintained as much — that the way in which man ingests his food, digests it, and incorporates it into his body is disgusting, one cannot argue the point with him. One must say to him: There is only this way or starvation." - Liberalism