Francis Wheen wrote an excellent biography of Karl Marx a few years ago, and is now back with Marx's Das Kapital: A Biography. I haven't seen the book yet, but you can read a reflection on it on spiked-online by Michael Fitzpatrick, who agrees with Wheen that Marx's 'Capital is unique, there is "nothing remotely like it".' Fitzpatrick relays his discovery of the brilliance of the book in the 1970s, and how it has become trendy again in the 1990s when it had apparently lost its subversive potential during the new period of capitalist triumphalism. Fitzpatrick correctly points out that against popular thinking, 'Marx does not advance a mechanistic thesis of collapse [of capitalism] or predict the inevitable downfall of capitalism.' Marx was not a fatalist but someone who saw the key factor of class struggle as changing the world.