The comparative analysis of socialist and capitalist economic systems has given rise to a voluminous literature in the history of economic thought, yet detailed analysis of the “market socialism” model, which seeks to imitate the functional efficiency of capitalism by simulating a competitive economy, has been relatively neglected. In this work, Mateusz Machaj seeks to redress this imbalance by providing an in-depth examination of one of the defining issues that separates capitalism from socialism – the system of ownership, or property rights – which, when explored, highlight fundamental problems in the market socialism model. Taking a broadly Austrian perspective, he shows that the mechanism of efficiency in market socialism is unable to play the part ascribed to it by its theoreticians, because it disregards the fact that property rights are fundamental to the shaping of prices and thus the abolition of ownership in market socialism makes its mechanism of efficiency a fiction. Indeed, the author argues, the economic terms used in the model of market capitalism only mirror the names of the real economic variables that cause capitalism to be efficient, not their functions. The books offers new and original insights into the theory of competition, theories of pricing, property laws, the relation between law and economics, as well as the economics of the market socialism model. It will be of interest to a wide range of heterodox economists.