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?
Sentence (from "Marxists Internet Archive"): It contains over 53,000 documents from over 600 authors in 61 languages.
Relevant evidence: No