Ludwig von Mises Became an Austrian Economist around Christmas 1903 When He Read Carl Menger's Book "Principles of Economics"

When I first arrived at the University, Carl Menger was close to the termination of his teaching career. The idea that there was an Austrian School of economics was itself hardly recognized at the University, and I myself was not at all interested in it at that time.

Around Christmas, 1903, I read Menger’s Grundsätze der Volkswirtschaftslehre [Principles of Economics] for the first time. It was the reading of this book that made an “economist” of me.

Personally I met Carl Menger only many years later. He was then already more than seventy years old, hard of hearing, and plagued by an eye disorder. But his mind was young and vigorous. Again and again I have asked myself why this man did not make better use of the last decades of his life.

--Ludwig von Mises, Notes and Recollections with the Historical Setting of the Austrian School of Economics, ed. Bettina Bien Greaves, trans. Hans Sennholz (Indianapolis: Liberty Fund, 2013), 22.