Marxism is a theory and method of working-class self-emancipation. As a theory, it relies on a method of socioeconomic analysis that views class relations and social conflict using a materialist interpretation of historical development and takes a dialectical view of social transformation. It originates from the works of 19th-century German philosophers Karl Marx and Friedrich Engels.

Karl Marx (5 May 1818 – 14 March 1883) was a German philosopher, political economist and socialist revolutionary who addressed the matters of alienation and exploitation of the working class, the capitalist mode of production and historical materialism. He is famous for analysing history in terms of class struggle, summarised in the initial line introducing The Communist Manifesto (1848): "The history of all hitherto existing society is the history of class struggles".

Friedrich Engels (28 November 1820 – 5 August 1895) was a German political philosopher who together with Marx co-developed communist theory. Marx and Engels first met in September 1844. Discovering that they had similar views of philosophy and socialism, they collaborated and wrote works such as Die heilige Familie (The Holy Family). After Marx was deported from France in January 1845, they moved to Belgium, which then permitted greater freedom of expression than other European countries. In January 1846, they returned to Brussels to establish the Communist Correspondence Committee.

In 1847, they began writing The Communist Manifesto (1848), based on Engels' The Principles of Communism. Six weeks later, they published the 12,000-word pamphlet in February 1848. In March, Belgium expelled them and they moved to Cologne, where they published the Neue Rheinische Zeitung, a politically radical newspaper. By 1849, they had to leave Cologne for London. The Prussian authorities pressured the British government to expel Marx and Engels, but Prime Minister Lord John Russell refused.

After Marx's death in 1883, Engels became the editor and translator of Marx's writings. With his Origins of the Family, Private Property, and the State (1884) – analysing monogamous marriage as guaranteeing male social domination of women, a concept analogous, in communist theory, to the capitalist class's economic domination of the working class—Engels made intellectually significant contributions to feminist theory and Marxist feminism.

According to orthodox Marxist theory, the overthrow of capitalism by a socialist revolution in contemporary society is inevitable. While the inevitability of an eventual socialist revolution is a controversial debate among many different Marxist schools of thought, all Marxists believe socialism is a necessity, if not inevitable. Marxists believe that a socialist society is far better for the majority of the populace than its capitalist counterpart. Prior to the Russian revolution of 1917, Lenin wrote: "The socialization of production is bound to lead to the conversion of the means of production into the property of society ... This conversion will directly result in an immense increase in productivity of labour, a reduction of working hours, and the replacement of the remnants, the ruins of small-scale, primitive, disunited production by collective and improved labour".[30] The failure of the 1905 revolution and the failure of socialist movements to resist the outbreak of World War One led to renewed theoretical effort and valuable contributions from Lenin and Rosa Luxemburg towards an appreciation of Marx's crisis theory and efforts to formulate a theory of imperialism.

Marx distinguishes social classes on the basis of two criteria: ownership of means of production and control over the labour power of others. Following this criterion of class based on property relations, Marx identified the social stratification of the capitalist mode of production with the following social groups:

Proletariat: " the class of modern wage labourers who, having no means of production of their own, are reduced to selling their labour power in order to live.
The capitalist mode of production establishes the conditions enabling the bourgeoisie to exploit the proletariat because the workers' labour generates a surplus value greater than the workers' wages.

Bourgeoisie: those who "own the means of production" and buy labour power from the proletariat, thus exploiting the proletariat. They subdivide as bourgeoisie and the petite bourgeoisie.
Petite bourgeoisie
are those who work and can afford to buy little labour power i.e. small business owners, peasant landlords, trade workers and the like. Marxism predicts that the continual reinvention of the means of production eventually would destroy the petite bourgeoisie, degrading them from the middle class to the proletariat.

Lumpenproletariat: the outcasts of society such as the criminals, vagabonds, beggars, or prostitutes without any political or class consciousness. Having no interest in international or national economics affairs, Marx claimed that this specific sub-division of the proletariat would play no part in the eventual social revolution.

Landlords: a historically important social class who retain some wealth and power.

Peasantry and farmers: a scattered class incapable of organizing and effecting socio-economic change, most of whom would enter the proletariat while some would become landlords.
Class consciousness denotes the awareness—of itself and the social world—that a social class possesses and its capacity to rationally act in their best interests, hence class consciousness is required before they can effect a successful revolution and thus the dictatorship of the proletariat.

Without defining ideology, Marx used the term to describe the production of images of social reality. According to Engels, "ideology is a process accomplished by the so-called thinker consciously, it is true, but with a false consciousness. The real motive forces impelling him remain unknown to him; otherwise it simply would not be an ideological process. Hence he imagines false or seeming motive forces". Because the ruling class controls the society's means of production, the superstructure of society (the ruling social ideas), are determined by the best interests of the ruling class. In The German Ideology, he says "the ideas of the ruling class are in every epoch the ruling ideas, i.e., the class which is the ruling material force of society, is, at the same time, its ruling intellectual force."

According to the Marxist theoretician and revolutionary Vladimir Lenin, "the principal content of Marxism" was "Marx's economic doctrine". Marx believed that the capitalist bourgeois and their economists were promoting what he saw as the lie that "the interests of the capitalist and of the worker are ... one and the same", therefore he believed that they did this by purporting the concept that "the fastest possible growth of productive capital" was best not only for the wealthy capitalists but also for the workers because it provided them with employment.

Exploitation is a matter of surplus labour—the amount of labour one performs beyond what one receives in goods. Exploitation has been a socioeconomic feature of every class society and is one of the principal features distinguishing the social classes. The power of one social class to control the means of production enables its exploitation of the other classes.

In capitalism, the labour theory of value is the operative concern; the value of a commodity equals the socially necessary labour time required to produce it. Under that condition, surplus value (the difference between the value produced and the value received by a labourer) is synonymous with the term "surplus labour", thus capitalist exploitation is realised as deriving surplus value from the worker.

In pre-capitalist economies, exploitation of the worker was achieved via physical coercion. In the capitalist mode of production, that result is more subtly achieved and because workers do not own the means of production, they must voluntarily enter into an exploitive work relationship with a capitalist in order to earn the necessities of life. The worker's entry into such employment is voluntary in that they choose which capitalist to work for. However, the worker must work or starve, thus exploitation is inevitable and the "voluntary" nature of a worker participating in a capitalist society is illusory.