"The Poverty of Philosophy" ("Misere de la Philosophie" was published in Paris and Brussels in 1847, where Marx lived in while 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." The book was regarded by the political circle around Marx, the Communist League, as a key part of their contemporary program, delineating the views of the League from those espoused by Proudhon and his followers. It was highly polemical and is not considered a canon of Marxism, though it remains of specialized interest.
