I found the book most illuminating and highly recommend it if you have not already read it. I do not know how he self describes his work in the stream of political economy but I would characterize him as "Post-Marxist".  The central thesis of the book is stated in the title and he develops that thesis in a manner that provides an examination of and contrast between "mainstream economics" and the Marxist tradition that is very helpful. The real value of the book is his illumination of the missing parts of both traditions, which, interestingly, have to do with the artificial separation of economics and politics into separate realms, and his real accomplishment is to show just how confounding that separation has been and how illuminating a reuniting of the two areas can be.

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."