Pierre Joseph Proudhon is a French politician, publicist, economist, philosopher and sociologist. “What is property? Or Studies on the Principle of Law and Power” - the author’s appeal to the concept of property and its relationship with power and law. He views property as an unfounded assignment of the right to a thing and provides arguments in defense of the fact that property is physically and mathematically impossible. The book is recommended for both specialists - political scientists, economists, sociologists, historians, philosophers, and a wide range of readers.