Question: Anarchy is the condition of a society, entity, group of people, or a single person that rejects hierarchy, the word originally meant leaderlessness, but in 1840, Pierre-Joseph Proudhon adopted the term in his treatise, titled what, an work of nonfiction on the concept of property and its relation to anarchist philosophy by the French anarchist and mutualist Pierre-Joseph Proudhon, first published in 1840?
Context: What Is Property? : or, An Inquiry into the Principle of Right and of Government (French: "Qu'est-ce que la propriété ?  ou Recherche sur le principe du Droit et du Gouvernement" ) is a work of nonfiction on the concept of property and its relation to anarchist philosophy by the French anarchist and mutualist Pierre-Joseph Proudhon, first published in 1840.  In the book, Proudhon most famously declared that "property is theft". Marxists Internet Archive (also known as MIA or Marxists.org) is a non-profit website that hosts a multilingual library (created in 1990) of the works of Marxist, communist, socialist, and anarchist writers, such as Karl Marx, Friedrich Engels, Vladimir Lenin, Leon Trotsky, Rosa Luxemburg, Che Guevara, Mikhail Bakunin, and Pierre-Joseph Proudhon, as well as that of writers of related ideologies, and even unrelated ones (for instance, Sun Tzu and Adam Smith).  The collection is maintained by volunteers, and is based on a collection of documents that were distributed by email and newsgroups, later collected into a single gopher site in 1993.  It contains over 53,000 documents from over 600 authors in 61 languages. Anarchist Manifesto (or The World's First Anarchist Manifesto) is a work by Anselme Bellegarrigue, notable for being the first manifesto of anarchism.  It was written in 1850, ten years after Pierre-Joseph Proudhon became history's first self-proclaimed anarchist with the publication of his seminal "What Is Property? ". Anarchy is the condition of a society, entity, group of people, or a single person that rejects hierarchy.  The word originally meant leaderlessness, but in 1840 Pierre-Joseph Proudhon adopted the term in his treatise "What Is Property? " to refer to a new political philosophy: anarchism, which advocates stateless societies based on voluntary associations.  In practical terms, anarchy can refer to the curtailment or abolition of traditional forms of government.  It can also designate a nation (or anywhere on earth that is inhabited) that has no system of government or central rule. Property is theft!  (French: "La propriété, c'est le vol!" )  is a slogan coined by French anarchist Pierre-Joseph Proudhon in his 1840 book "What is Property?  Or, an Inquiry into the Principle of Right and of Government". Anarchism in France can trace its roots to thinker Pierre-Joseph Proudhon, who grew up during the Restoration and was the first self-described anarchist.  French anarchists fought in the Spanish Civil War as volunteers in the International Brigades.  According to journalist Brian Doherty, "The number of people who subscribed to the anarchist movement's many publications was in the tens of thousands in France alone." Karl Theodor Ferdinand Grűn (] ; 30 September 1817 – 18 February 1887), also known by his alias Ernst von der Haide, was a German journalist, political theorist and socialist politician.  He played a prominent role in radical political movements leading up to the Revolution of 1848 and participated in the revolution.  He was an associate of Heinrich Heine, Ludwig Feuerbach, Pierre-Joseph Proudhon, Karl Marx, Mikhail Bakunin and other radical political figures of the era.  Though less widely known today, Grün was an important figure in the German "Vormärz", Young Hegelian philosophy and the democratic and socialist movements in nineteenth-century Germany.  As a target of Marx' criticism, Grün played a role in the development of early Marxism; through his philosophical influence on Proudhon, he had a certain influence on the development of French socialist theory. Mutualism is an economic theory and anarchist school of thought that advocates a society where each person might possess a means of production, either individually or in purely voluntary collectives, with trade representing equivalent amounts of labor in the free market.  Integral to the scheme is the establishment of a mutual-credit bank that would lend to producers at a minimal interest rate, just high enough to cover administration.  Mutualism is based on a labor theory of value that holds that when labor or its product is sold, in exchange, it ought to receive goods or services embodying "the amount of labor necessary to produce an article of exactly similar and equal utility".  Mutualism originated from the writings of philosopher Pierre-Joseph Proudhon. Pierre-Joseph Proudhon (] ; 15 January 1809 – 19 January 1865) was a French politician and the founder of mutualist philosophy.  He was the first person to declare himself an anarchist and is widely regarded as one of the ideology's most influential theorists.  Proudhon is even considered by many to be the "father of anarchism".  He became a member of the French Parliament after the revolution of 1848, whereafter he referred to himself as a federalist. The Poverty of Philosophy ( "Misère de la philosophie") is a book by Karl Marx published in Paris and Brussels in 1847, where he lived in exile from 1843 until 1849.  It was originally written in French as an answer to the economic and philosophical arguments of French anarchist Pierre-Joseph Proudhon set forth in his 1846 book "The System of Economic Contradictions, or The Philosophy of Poverty."
Answer: What Is Property?