The theory of Marxism lies near the heart of the European problem of the secular. To consider Marx would be necessary in itself. It is the more necessary because of modern progress in Marx studies. Formerly men used to see Marx with spectacles of the tradition; influenced, consciously or not, by the eyes and formulations of Lenin, and still more by the eyes and formulations of Engels; inevitably by Engels, because of the nature of the association between the two men; and because Engels so long outlived his partner and continued to expound his mind. The original critical edition of the Marx- Engels corpus of work, edited by Riazanov, was stopped by the Stalin purges, and the Stalinist epoch fossilized intellectual Marxism. Only from 1957 has East Berlin published the fuller critical edition. Since the standard commentators fixed the tradition, the early writings of Marx, collected in small part from manuscript, cast a brilliant light upon his mind and philosophy.

He became thereby no easier for expositors. Did his mind change over the years and are the early texts reliable for his mature judgment? Engels wrote two books with Marx, they wrote regular letters to each other, consulted each other. No discovery of manuscripts could drive a wedge between the two authors. And yet Engels had the less subtle mind of the two. He made Marx simpler, or cruder, to make him intelligible.