Obviously going to be lots of "tl;dr" here, so I'll summarize:<p>Piketty's capitalism is all about numbers, Marx's was about social relations. Author preferred Marx. Author believes they have to be about the same thing because they have the same title.<p>I agree with the author in his critique, but like most critiques, they're more about the way the critic would have done it (but didn't) than about what is valuable within the work. Still, it's important to remember that beyond all the statistics, the social relations <i>mean</i> something.