Isaiah Berlin’s intellectual biography of Karl Marx has long been recognized as one of the best concise accounts of the life and thought of the man who had, in Berlin’s words, a more direct, deliberate, and powerful influence on mankind than any other nineteenth-century thinker. A brilliantly lucid work of synthesis and exposition, the book introduces Marx’s ideas and sets them in their context, explains why they were revolutionary in political and intellectual terms, and paints a memorable portrait of Marx’s dramatic life and outsized personality. Berlin takes readers through Marx’s years of adolescent rebellion and post-university communist agitation, the personal high point of the 1848 revolutions, and his later years of exile, political frustration, and intellectual effort. Critical yet sympathetic, Berlin’s account illuminates a life without reproducing a legend. New features of this thoroughly revised edition include references for Berlin’s quotations and allusions, Terrell Carver’s assessment of the distinctiveness of Berlin’s book, and a revised guide to further reading.