“For the proletariat to be strong enough to win on the decisive day, it must … form a separate party distinct from all others and opposed to them, a conscious class party.” Frederick Engels 
The Communist Manifesto made clear in its opening sentence that the history of all hitherto existing society is the history of class struggles. While the central thesis of the Manifesto is that the development and growth of capitalism creates the conditions for a class struggle, workers must organise themselves as a class and engage in a programme of action in political struggle to overthrow the capitalist system. For that purpose workers require a class conscious party capable of performing that role. As the Manifesto explains:
"The Communists, therefore, are on the one hand, practically, the most advanced and resolute section of the working-class parties of every country, that section which pushes forward all others; on the other hand, theoretically, they have over the great mass of the proletariat the advantage of clearly understanding the line of march, the conditions, and the ultimate general results of the proletarian movement." 
Writing of the Communist Manifesto Lenin said: “This little booklet is worth whole volumes: to this day its spirit inspires and guides the entire organised and fighting proletariat of the civilised world.” 
The task of establishing a revolutionary workers’ party capable of leading the struggle for the emancipation of the working class and the construction of a socialist society remains a fundamental preoccupation for those interested in socialist revolution and the overthrow of capitalism.
“What is to be Done?” was Lenin’s seminal work on the party. Once the work was translated into other languages in the early years of the Russian Revolution, it became the framework on which Communist and Workers’ Parties across the globe organised themselves. On the 100th anniversary of the October Socialist Revolution we have much to learn from the Bolshevik experience.
In tsarist Russia, the Russian Social Democratic and Labour Party (RSDLP) was illegal: its members were subject to imprisonment and deportation to Siberia, and its leaders, including Lenin, were in exile abroad. Police repression meant that the party lacked a continuous structure as after each round of arrests in a given area, the process of building the party would have to start from scratch. What is to Be Done? set out a plan for developing the RSDLP in underground conditions. The work was written to address a number of major questions facing the RSDLP concerning ideology, strategy, and party organisation.
Internationally, Social Democrats were divided between those who continued to believe in the need for revolution and those embracing reformism. The leading thinker among the reformists at that time was the German theorist, Eduard Bernstein. Bernstein, who was influenced by the Fabians during his time in London, presented the argument that capitalism had developed a facility for modification which would obviate future economic crises. Rejecting the concept of dialectical materialism he concluded that the abolition of capitalism and the creation of socialist revolution was both impossible and unnecessary. International Bernsteinism was one of Lenin’s ideological targets, but he also criticised others closer to home, namely supporters of economism and terrorism.
“Economism” was how Lenin described the idea that in the circumstances of Tsarist Russia Social Democrats ought to neglect or even avoid political struggle. The “Economists” explicitly rejected the concept of a party programme consisting of political demands. They sought to confine themselves to agitation on economic issues.
The “Economists” believed that because Russia had yet to make the transition from a feudal absolute monarchy to a capitalist representative system of government, political struggle against the tsarist regime was primarily the job of the middle classes as it was their task to carry out the bourgeois revolution that would establish a new system of government and that it was too early for the development of a political party of the working class.
To Lenin, such arguments were not simply foolish: they were highly damaging to the consciousness and interests of the working class. Lenin believed that unless the working class organised itself politically and unless it embraced the struggle for democracy in Russia, no serious progress could be made in building socialism. He re-stated the vital proposition contained in the Communist Manifesto that every class struggle is a political struggle. In other words, “Economism” was a cancer in Russian Social Democracy that had to be excised. Lenin therefore set about undermining Economism and its chief adherents in What is to Be Done?
The failure to realise the importance of political struggle was a problem not only in Russia. Lenin condemned what he called “trade unionism” (the idea that trade unions were the main means of struggle for workers, and that workers should be interested in politics primarily to meet trade union demands, e.g. legally limiting the length of the working day). Lenin associated both economism and trade unionism with Bernsteinism: in his view, they were a means of stripping Social Democracy of its revolutionary content, thus embracing bourgeois ideology masquerading as socialism.
Terrorism was in Lenin’s eyes a different yet similar threat to the struggle for socialism. There was a strong tradition of terrorism among Russian revolutionaries, both socialist and liberal. For example, Tsar Alexander II had been assassinated in 1881. Lenin’s own brother had been executed for his role in a plot to kill Alexander III. A number of prominent officials within the tsarist regime had also been assassinated. There were those within Russian Social Democracy who believed that terrorism could be an effective weapon in the struggle against the absolute monarchy.
Lenin did not accept this. For him, terrorism wasted the lives and energy of revolutionaries, and it had been proven to be ineffective. As with economism, in his eyes the popularity of terrorism with some Social Democrats reflected the weakness of the Russian Social Democratic and Labour Party. The party lacked ideological clarity, and it had failed to sufficiently raise the political consciousness of its own members, as well as the workers’ movement in general. What is to Be Done? was written in large part to provide greater ideological clarity for, and to raise the political consciousness of, the members of the RSDLP.
Earlier, in Articles for Rabochaya Gazeta written in the second half of 1899 Lenin had stated: “We take our stand entirely on the Marxist theoretical position: Marxism was the first to transform socialism from a utopia into a science, to lay a firm foundation for this science, and to indicate the path that must be followed in further developing and elaborating it in all its parts. It disclosed the nature of modern capitalist economy by explaining how the hire of the labourer, the purchase of labour-power, conceals the enslavement of millions of propertyless people by a handful of capitalists, the owners of the land, factories, mines, and so forth. It showed that all modern capitalist development displays the tendency of large-scale production to eliminate petty production and creates conditions that make a socialist system of society possible and necessary. It taught us how to discern, beneath the pall of rooted customs, political intrigues, abstruse laws, and intricate doctrines - the class struggle, the struggle between the propertied classes in all their variety and the propertyless mass, the proletariat, which is at the head of all the propertyless.” As Lenin stated the real task of a revolutionary socialist party was: “not to draw up plans for refashioning society, not to preach to the capitalists and their hangers-on about improving the lot of the workers, not to hatch conspiracies, but to organise the class struggle of the proletariat and to lead this struggle, the ultimate aim of which is the conquest of political power by the proletariat and the organisation of a socialist society.”
The Second Congress of the Russian Social Democratic Labour Party marked the beginning of the Bolshevik Party, a party of socialist revolution.
By the mid-19th century the productive forces created under capitalism began to outgrow the capitalist relations of production. By the turn of the century capitalism had entered its highest stage, imperialism, and was characterised by a sharpening of contradictions in the capitalist system.
In September 1902 Lenin spoke of the necessity for “a disciplined party of struggle”.  In One Step Forward: Two Steps back – The Crisis in Our Party written in 1904 he developed the principles required for building such a party. In the struggle to build a disciplined party Lenin demonstrated the importance of resisting those forces determined to liquidate the party, and the otzovists, opportunists and reformists.These lessons remain valid today.
In the course of the first Russian Revolution the working class created Soviets of Workers’ Deputies. Lenin described the Soviets as the beginnings of a new type of government.
On 5 December 1905 the Moscow Bolsheviks adopted a resolution on beginning a general strike which was to develop into armed struggle. The December Uprising, treacherously opposed by the Mensheviks and the Socialist-Revolutionaries, was suppressed. The Bolsheviks, however, learned lessons from the defeat concluding that an armed uprising is a very serious matter and that the time for an uprising must be chosen carefully to avoid premature action which might prejudice its potential for success, and that proper and careful ideological and practical preparations must be in place.
The 1905-07 revolution failed to achieve its objectives for a number of reasons but the workers had demonstrated how it might have succeeded. The defeat was only a temporary respite for Tsarism although it did engage in a campaign of savage reprisals designed to destroy the impetus for revolution and its revolutionary party. Lenin was again forced abroad. The Bolsheviks learned important lessons, including the need to develop new tactics to adapt to changing circumstances, and Lenin later referred to the revolution as the dress rehearsal for October 1917. It demonstrated that the working class was the leading revolutionary force. By contrast the defeat left the Mensheviks demoralised. The ultra-leftist otzovists also failed to learn the lessons. While those such as Trotsky wavered and dissembled others such as Lenin, Sverdlov, Ordzhonikidze and Dzerzhinsky paid the price of arrest, imprisonment and exile.
Lenin writing in Proletary in November 1908 stated: “The fact remains that disunity and wavering exist, and this fact calls for an explanation. And there can be no other explanation than the necessity of a new sorting out … In the interests of this new sorting-out a strengthening of theoretical work is essential. The “present moment” in Russia is precisely one in which the theoretical work of Marxism, its deepening and expansion, are dictated not by the state of mind of this or that individual, not by the enthusiasm of one or another group, and not even by the external police conditions which have condemned many to elimination from “practical work"—but by the whole objective state of affairs in the country. When the masses are digesting a new and exceptionally rich experience of direct revolutionary struggle, the theoretical struggle for a revolutionary outlook, i.e., for revolutionary Marxism, becomes the watchword of the day.”