In the beginning, there was Menger. It was this book that reformulated, and really rescued, economic science. It kicked off the Marginalist Revolution, which corrected theoretical errors of the old classical school. These errors concerned value theory, and they had sown enough confusion to make the dangerous ideology of Marxism seem more plausible than it really was. Menger set out to elucidate the precise nature of economic value, and root economics firmly in the real-world actions of individual human beings. For this reason, Carl Menger (1840-1921) was the founder of the Austrian School of economics. It is the book that Mises said turned him into a real economist. What's striking is how nearly a century and a half later, the book still retains its incredible power, both in its prose and its relentless logic. The Mises Institute's new edition features a new foreword by Peter G. Klein, which summarizes Menger's contribution and places him in the history of ideas. He also explains his continued relevance. Economics students still say that it is the best introduction to economic logic ever written. The book also deserves the status of a seminal contribution to science in general. Truly, no one can claim to be well read in economics without having mastered Menger's argument. Menger advances his theory that the marginal utility of goods is the source of their value, not the labor inputs that went into making them. The implication is that the individual mind is