Walter Edward Block (born August 21, 1941) is an American Austrian School economist and anarcho-capitalist theorist. He currently holds the Harold E. Wirth Eminent Scholar Endowed Chair in Economics at the J. A. Butt School of Business at Loyola University New Orleans. He is a senior fellow of the Ludwig von Mises Institute in Auburn, Alabama. He is best known for his 1976 book Defending the Undefendable.