Peter Gordon in The New Republic:
There have been many biographies of Karl Marx, and most of them fit into the first category. This is understandable, because until recently most people saw Marx as the founding father in a drama of communism that was still unfolding across the globe. Celebrated or excoriated, Marx seemed very much our contemporary, a man whose explosive ideas and personality continued to fascinate. One of the earliest efforts waspublished in 1918 by Franz Mehring, a journalist who helped Rosa Luxemburg and Karl Liebknecht in founding the Spartacus League (soon renamed the German Communist Party). He was not what you would call an unbiased source. Mehring wished to portray Marx “in all his powerful and rugged greatness.” After summarizing the second and third (never-completed) volumes of Capital he assured the reader that their pages contain a “wealth of intellectual stimulation” for “enlightened workers.”
Less partisan was Karl Marx: His Life and Environment by Isaiah Berlin, which appeared in 1939. In many respects, Berlin was the ideal person for the job, since he understood the inner workings of Marx’s theory but remained sensitive to its complicated and catastrophic political consequences. He was not completely unsympathetic: like Marx, Berlin was a cosmopolitan of Jewish descent who fled persecution on the Continent and ended up in England. Unlike Marx, Berlin assimilated to British custom and made a career of defending liberal pluralism against totalitarian thinking right and left. But Berlin’s skepticism did not prevent him from comprehending Marx’s ideas. A good biographer needs critical distance, not ardent identification. His book, a perennial classic, has all the virtues of Berlin himself: charm, erudition, and (occasionally) grandiloquence.
Over the last century, a handful of previously unknown writings by Marx have come to light, and they have modified the way we understand his legacy. The most important of these were the “Economic and Philosophic Manuscripts” of 1844, often known as the “Paris manuscripts,” dense and speculative texts that were discovered in the late 1920s and first published in 1932. They are significant because they give us a glimpse of the young Marx as a humanist and a metaphysician whose theory of alienation relied on the Hegelian themes that he absorbed while a student at the University of Berlin.