refers to these works in his own writings; he looked to them for guidance upon the most important problems of the proletarian revolution. There is no doubt that the passages in the correspondence of Marx and Engels dealing with the American labor movement ought to come under this head. These letters cover the historical content of an entire generation—from 1868 to 1895.
Leninism is not, as several opportunists maintain, only a sub-division of Marxism. It is neither the Marxism of the "early period" nor the Marxism of the "mature period." Leninism is the whole of Marxism in the epoch of imperialism and of the proletarian revolution. But no Chinese wall separates the epoch of imperialism from the epoch of the capitalism of free competition. Between the epoch of the bourgeois-democratic revolution and the epoch of the proletarian world revolution there lie no insuperable barriers. Between them there lies a period of transition. In the ranks of revolutionary Marxism this period of transition in its broadest sense is embodied in the left, revolutionary wing of the Second International. In a narrow sense it is expressed in the work of Marx's and Engels' concluding years, which historically already tower over the period prior to the Paris Commune and almost directly intertwine with the foundations of Leninism.
For this reason it is not admissable to consider the statements of Marx and Engels upon the problems of the American labor movement as "quotations from a bygone period." They belong rather, to the tactical doctrines of Marx and
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