structural:reformatting, quality:correction
New-York Daily Tribune and journalism

In the early period in London, Marx committed himself almost exclusively to his studies, such that his family endured extreme poverty. His main source of income was Engels, whose own source was his wealthy industrialist father. In Prussia as editor of his own newspaper, and contributor to others ideologically aligned, Marx could reach his audience, the working classes. In London, without finances to run a newspaper themselves, he and Engels turned to international journalism. At one stage they were being published by six newspapers from England, the United States, Prussia, Austria, and South Africa. Marx's principal earnings came from his work as European correspondent, from 1852 to 1862, for the New-York Daily Tribune, and from also producing articles for more "bourgeois" newspapers. Marx had his articles translated from German by Wilhelm Pieper, until his proficiency in English had become adequate.

The New-York Daily Tribune had been founded in April 1841 by Horace Greeley. Its editorial board contained progressive bourgeois journalists and publishers, among them George Ripley and the journalist Charles Dana, who was editor-in-chief. Dana, a fourierist and an abolitionist, was Marx's contact. The Tribune was a vehicle for Marx to reach a transatlantic public, such as for his "hidden warfare" against Henry Charles Carey. The journal had wide working-class appeal from its foundation; at two cents, it was inexpensive; and, with about 50,000 copies per issue, its circulation was the widest in the United States. Its editorial ethos was progressive and its anti-slavery stance reflected Greeley's. Marx's first article for the paper, on the British parliamentary elections, was published on 21 August 1852.

On 21 March 1857, Dana informed Marx that due to the economic recession only one article a week would be paid for, published or not; the others would be paid for only if published. Marx had sent his articles on Tuesdays and Fridays, but, that October, the Tribune discharged all its correspondents in Europe except Marx and B. Taylor, and reduced Marx to a weekly article. Between September and November 1860, only five were published. 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. In 1868, Dana set up a rival newspaper, the New York Sun, at which he was editor-in-chief. In April 1857, Dana invited Marx to contribute articles, mainly on military history, to the New American Cyclopedia, an idea of George Ripley, Dana's friend and literary editor of the Tribune. In all, 67 Marx-Engels articles were published, of which 51 were written by Engels, although Marx did some research for them in the British Museum. By the late 1850s, American popular interest in European affairs waned and Marx's articles turned to topics such as the "slavery crisis" and the outbreak of the American Civil War in 1861 in the "War Between the States". Between December 1851 and March 1852, Marx worked on his theoretical work about the French Revolution of 1848, titled The Eighteenth Brumaire of Louis Napoleon. In this he explored concepts in historical materialism, class struggle, dictatorship of the proletariat, and victory of the proletariat over the bourgeois state.

The 1850s and 1860s may be said to mark a philosophical boundary distinguishing the young Marx 's Hegelian idealism and the more mature Marx 's scientific ideology associated with structural Marxism. However, not all scholars accept this distinction. For Marx and Engels, their experience of the Revolutions of 1848 to 1849 were formative in the development of their theory of economics and historical progression. After the "failures" of 1848, the revolutionary impetus appeared spent and not to be renewed without an economic recession. Contention arose between Marx and his fellow communists, whom he denounced as "adventurists". Marx deemed it fanciful to propose that "will power" could be sufficient to create the revolutionary conditions when in reality the economic component was the necessary requisite. The recession in the United States' economy in 1852 gave Marx and Engels grounds for optimism for revolutionary activity, yet this economy was seen as too immature for a capitalist revolution. Open territories on America's western frontier dissipated the forces of social unrest. Moreover, any economic crisis arising in the United States would not lead to revolutionary contagion of the older economies of individual European nations, which were closed systems bounded by their national borders. When the so-called Panic of 1857 in the United States spread globally, it broke all economic theory models, and was the first truly global economic crisis.