Many attempts have been made over the years to ‘update’ Marx’s economic theories. Inevitably, these ideas jettison the revolutionary core of Marxist economics. Instead of applying a dialectical and materialist method to the economy, the revisionists slip into a mechanical and idealist mode of analysis. They do not see the economy as a living, breathing system, composed of human beings and conflicting classes, but as a set of abstract equations. This discussion will set the record straight, show how these revisionist ideas fall short, and give an overview of genuine Marxist economic theory. Our speaker, Rob Sewell, is a leading activist of Socialist Appeal, British section of the IMT.