Very informative post, The term "utopian socialism" was introduced by Karl Marx in "For a Ruthless Criticism of Everything" in 1843 (and then developed in The Communist Manifesto in 1848), although shortly before its publication Marx had already attacked the ideas of Pierre-Joseph Proudhon in Das Elend der Philosophie (originally written in French, 1847). The term was used by later socialist thinkers to describe early socialist or quasi-socialist intellectuals who created hypothetical visions of egalitarian, communalist, meritocratic, or other notions of "perfect" societies without considering how these societies could be created or sustained.