"Principles of Economics" by Carl Menger is a seminal work in the field of economics, laying the foundation for the Austrian School of Economics. First published in 1871, Menger's book revolutionized economic thought by emphasizing the subjective nature of economic value and the role of individual preferences in determining prices. Menger's analysis of marginal utility and his explanation of how goods derive their value from their ability to satisfy human wants mark significant departures from classical economic theories prevalent at the time. This book remains essential reading for anyone interested in understanding the fundamentals of economic theory and the origins of modern economic thought.