He is best-known for the 1848 pamphlet The Communist Manifesto (written with Friedrich Engels), and his three-volume Das Kapital (1867–1894), a critique of classical political economy which employs his theory of historical materialism in an analysis of capitalism, in the culmination of his life's work.

Like Marx, the Young Hegelians were critical of Hegel's metaphysical assumptions but adopted his dialectical method to criticise established society, politics and religion from a left-wing perspective.

[51] Marx moved to Cologne in 1842, where he became a journalist, writing for the radical newspaper Rheinische Zeitung (Rhineland News), expressing his early views on socialism and his developing interest in economics.

[71] During the time that he lived at 38 Rue Vaneau in Paris (from October 1843 until January 1845),[72] Marx engaged in an intensive study of political economy (Adam Smith, David Ricardo, James Mill, etc.

[75] The study of, and critique, of political economy is a project that Marx would pursue for the rest of his life[76] and would result in his major economic work—the three-volume series called Das Kapital.

[81][84] This work contains Marx's criticism of materialism (for being contemplative), idealism (for reducing practice to theory), and, overall, philosophy (for putting abstract reality above the physical world).

[81][95][96] After completing German Ideology, Marx turned to a work that was intended to clarify his own position regarding "the theory and tactics" of a truly "revolutionary proletarian movement" operating from the standpoint of a truly "scientific materialist" philosophy.

[100] As noted above, Marx thought the League to be just the sort of radical organisation that was needed to spur the working class of Europe toward the mass movement that would bring about a working-class revolution.

Proceeding on from this, the Manifesto presents the argument for why the Communist League, as opposed to other socialist and liberal political parties and groups at the time, was truly acting in the interests of the proletariat to overthrow capitalist society and to replace it with socialism.

[113] Although the veracity of these allegations is disputed,[111][114] the Belgian Ministry of Justice accused Marx of it, subsequently arresting him and he was forced to flee back to France, where with a new republican government in power he believed that he would be safe.

[125][124][126] Meanwhile, the democratic parliament in Prussia collapsed and the king, Frederick William IV, introduced a new cabinet of his reactionary supporters, who implemented counterrevolutionary measures to expunge left-wing and other revolutionary elements from the country.

After a six-month interval, Marx resumed contributions from September 1861 until March 1862, when Dana wrote to inform him that there was no longer space in the Tribune for reports from London, due to American domestic affairs.

[162][163] Given the repeated failures and frustrations of workers' revolutions and movements, Marx also sought to understand and provide a critique suitable for the capitalist mode of production, and hence spent a great deal of time in the reading room of the British Museum studying.

[185] In a letter to Vera Zasulich dated 8 March 1881, Marx contemplated the possibility of Russia's bypassing the capitalist stage of development and building communism on the basis of the common ownership of land characteristic of the village mir.

In her obituary, penned by Friedrich Engels, her role is revealed as: "Marx took counsel of Helena Demuth, not only in difficult and intricate party matters, but even in respect of his economical writings".

A third affliction, eruption of carbuncles or boils, "was probably brought on by general physical debility to which the various features of Marx's style of life – alcohol, tobacco, poor diet, and failure to sleep – all contributed.

[204][205] Research from contemporary sources identifies thirteen named individuals attending the funeral: Friedrich Engels, Eleanor Marx, Edward Aveling, Paul Lafargue, Charles Longuet, Helene Demuth, Wilhelm Liebknecht, Gottlieb Lemke, Frederick Lessner, G Lochner, Sir Ray Lankester, Carl Schorlemmer and Ernest Radford.

The tomb at the new site, unveiled on 14 March 1956,[212] bears the carved message: "Workers of All Lands Unite", the final line of The Communist Manifesto; and, from the 11th "Thesis on Feuerbach" (as edited by Engels), "The philosophers have only interpreted the world in various ways—the point however is to change it".

Within twenty-five years of his death, the continental European socialist parties that acknowledged Marx's influence on their politics had contributed to significant gains in their representative democratic elections.

[231][232] For both Marx and Hegel, self-development begins with an experience of internal alienation stemming from this recognition, followed by a realisation that the actual self, as a subjective agent, renders its potential counterpart an object to be apprehended.

[81][152] On one hand, in the 19th century's deepest critique of the dehumanising aspects of this system he noted that defining features of capitalism include alienation, exploitation and recurring, cyclical depressions leading to mass unemployment.

[219] The problem is the "cancerous cell" of capital, understood not as property or equipment, but the social relations between workers and owners, (the selling and purchasing of labour power) – the societal system, or rather mode of production, in general.

[4]Marx believed that those structural contradictions within capitalism necessitate its end, giving way to socialism, or a post-capitalistic, communist society: The development of modern industry, therefore, cuts from under its feet the very foundation on which the bourgeoisie produces and appropriates products.

[215] Marx argued in The German Ideology that capitalism will end through the organised actions of an international working class: Communism is for us not a state of affairs which is to be established, an ideal to which reality will have to adjust itself.

[254] Marx theorised that between capitalism and the establishment of a socialist/communist system, would exist a period of dictatorship of the proletariat – where the working class holds political power and forcibly socialises the means of production.

Either Asiatic barbarism, under Muscovite direction, will burst around its head like an avalanche, or else it must re-establish Poland, thus putting twenty million heroes between itself and Asia and gaining a breathing spell for the accomplishment of its social regeneration.

"[263] According to the Stanford Encyclopedia of Philosophy: "Marx's analysis of colonialism as a progressive force bringing modernization to a backward feudal society sounds like a transparent rationalization for foreign domination.

He has been cited as one of the 19th century's three masters of the "school of suspicion", alongside Friedrich Nietzsche and Sigmund Freud,[270] and as one of the three principal architects of modern social science along with Émile Durkheim and Max Weber.

It has also been a line of thinking pursued by thinkers and activists such as Antonio Gramsci who have sought to understand the opportunities and the difficulties of transformative political practice, seen in the light of Marxist social theory.

[284] Major world leaders including Vladimir Lenin,[284] Mao Zedong,[285] Fidel Castro,[286] Salvador Allende,[287] Josip Broz Tito,[288] Kwame Nkrumah,[289] Jawaharlal Nehru,[290] Nelson Mandela,[291] Xi Jinping[292] and Thomas Sankara[293] have all cited Marx as an influence.