The whole struggle of our Party (and of the working class movement in Europe generally) must be directed against opportunism. The latter is not a current of opinion, not a tendency; it (opportunism) has now become the organised tool of the bourgeoisie within the working class movement.

Unity is a great thing and a great slogan. But what the workers’ cause needs is the unity of Marxists, not unity between Marxists, and opponents and distorters of Marxism.

Lenin, the greatest man of action in our century and at the same time the most selfless.

You have read and heard that communist theory-the science of communism created in the main by Marx, this doctrine of Marxism-has ceased to be the work of a single socialist of the nineteenth century, even though he was a genius, and that it has become the doctrine of millions and tens of millions of proletarians all over the world, who are applying it in their struggle against capitalism.

Only by abolishing private property in land and building cheap and hygienic dwellings can the housing problem be solved.

Unity must be won, and only the workers, the class-conscious workers themselves can win it - by stubborn and persistent effort.

The natural scientist must be a modern materialist, a conscious adherent of the materialism represented by Marx, i.e., he must be a dialectical materialist.