“The basis of modern economics is the cognition that it is precisely the disparity in the value attached to the objects exchanged that results in their being exchanged.  People buy and sell only because they appraise the things given up less than those received.  Thus the notion of a measurement of value is vain.  An act of exchange is neither preceded nor accompanied by any process which could be called a measuring of value.”

—Ludwig von Mises, Human Action: A Treatise on Economics

Gitta Serény, Mises’ stepdaughter, who recently passed, is mentioned in several places in Jörg Guido Hülsmann’s biography of Mises.  At one point, for a while, Mises and his wife were desperate to know whether Gitta escaped from Nazi-occupied France.  Here Hülsmann discusses Gitta’s memory of Mises’ love for music.

This article is chapter 4 from Economic Controversies (2011).
It originally appeared in The Foundations of Modern Austrian Economics (1976).