This book is an excellent history of the Paris Commune. Its author Lissagaray was a direct participant and fought for the Commune on the barricades. He collected testimonies from the survivors in exile in London, Switzerland and consulted all documents available at the time to ensure accuracy. He was assisted by Karl Marx in the writing of this classic, which was translated to English by Eleanor Marx.

Critique of the Gotha Programme is a critique of the draft programme of the United Workers' Party of Germany. In this document Marx address the dictatorship of the proletariat, the period of transition from capitalism to communism, the two phases of communist society, the production and distribution of the social goods, proletarian internationalism, and the party of the working class.

"The anti-authoritarians demand that the political state be abolished at one stroke, even before the social conditions that gave birth to it have been destroyed. They demand that the first act of the social revolution shall be the abolition of authority. Have these gentlemen ever seen a revolution? A revolution is certainly the most authoritarian thing there is; it is the act whereby one part of the population imposes its will upon the other part by means of rifles, bayonets and cannon—authoritarian means, if such there be at all."

Written by Karl Marx as an address to the General Council of the International, with the aim of distributing to workers of all countries a clear understanding of the character and world-wide significance of the heroic struggle of the Communards and their historical experience to learn from. The book was widely circulated by 1872 it was translated into several languages and published throughout Europe and the United States.

Value, Price and Profit was produced at a time when the labour theory of value had already matured in Marx’s brain. It was first delivered as a speech delivered by Marx to the International Working Men's Association (The First International) in June 1865, while he was working on the first volume of Capital that was published two years later.

The Preface of the Critique contains the first connected account of one of Marx's main theories: the materialist conception of history. The participants in history may not always be aware of what motives drive them, seeking instead to rationalise them in one way or another, but those motives exist and have a basis in the real world.

This work represents Marx's analysis of Napoleon III's coup d'etat of December 1851, which provides him with an opportunity for a meticulous examination of the ebb and flow of political forces and social classes in the period preceding Napoleon's seizure of power. Marx digs beneath the surfaces of political rhetoric and the manoeuvring for power by political personalities, and reveals the social forces and mechanisms at work during the political crisis. Its value, then, is as a class analysis of a political crisis.

"This work was Marx's first attempt, with the aid of his materialist conception, to explain a section of contemporary history from the given economic situation. Here the question was to demonstrate the inner causal connection in the course of a development which extended over some years, a development as critical, for the whole of Europe, as it was typical; that is, in accordance with the conception of the author, to trace political events back to the effects of what are, in the last resort, economic causes." (introduction by Engels)

This pamphlet was commissioned by the Communist League in 1847 and was first published on February 21, 1848. It was co-written by Karl Marx and Frederick Engels and is probably the most influential political writing of all time. It outlines the basic perspectives of what would subsequently be referred to as “Marxism.” These ideas have formed the basis for revolutionary struggles throughout the world up to the present day.

Wage Labour and Capital is based on lectures delivered by Marx at the German Workingmen’s Club of Brussels in 1847, that is, before the Communist Manifesto and at a time when Marx had not yet fully developed his theories of political economy. Although it is an early work, Wage Labour and Capital contains the outline of the Labour Theory of Value and many important insights into the workings of the capitalist system and the way in which workers are exploited.

The first Marxist FAQ, written by Friedrich Engels in 1847.

The Condition of the Working Class in England is a study of the industrial working class in Victorian England. Engels' first book, it was originally written in German as Die Lage der arbeitenden Klasse in England; an English translation was published in 1885. It was written during Engels' 1842–44 stay in Manchester, the city at the heart of the Industrial Revolution, and compiled from Engels' own observations and detailed contemporary reports. After their first meeting in 1844, Karl Marx read and was profoundly impressed by the book.

With Marx philosophy finally emerges out of the dark and airless cellar to which it was confined for centuries by scholastic thought and dragged out, blinking, into the light of day. Here at last thought is united with activity – not the one-sided purely intellectual activity of the scholar but real, sensuous human activity. 

Karl Marx understood very well the role of religion. He is often quoted as saying that religion is the “opium of the people”. But he said a lot more than that, and it was in this work that he shows a deep understanding of why people are religious. He explains that, to ask them to give up on their religious illusions, this means removing the conditions that require that illusion.