"Murray N. Rothbard, a scholar of extraordinary range, made major contributions to economics, history, political philosophy, and legal theory. He developed and extended the Austrian economics of Ludwig von Mises, in whose seminar he was a main participant for many years. He established himself as the principal Austrian theorist in the latter half of the twentieth century and applied Austrian analysis to historical topics such as the Great Depression of 1929 and the history of American banking.
"Rothbard was no ivory-tower scholar, interested only in academic controversies. Quite the contrary, he combined Austrian economics with a fervent commitment to individual liberty. He developed a unique synthesis that combined themes from nineteenth-century American individualists such as Lysander Spooner and Benjamin Tucker with Austrian economics. A new political philosophy was the result, and Rothbard devoted his remarkable intellectual energy, over a period of some forty-five years, to developing and promoting his style of libertarianism. In doing so, he became a major American public intellectual.
Here's a quote from his Man Economy and State (Page 1314) that is profound:
"The State produces nothing; it can only confiscate the production of others. The State, therefore, can guarantee nothing; if the requisite minimum is not produced, the State will have to default on its pledges. Of course the State can print all the money it wants, but it cannot produce the needed goods. Furthermore, the State cannot, in this way, provide security for every man alike. It can make some secure only at the expense of others." [More… PDF]
