The point of this publication is to link Marx's mature works to political action, in the hope of outlining effective principles of activism.  Marx's final work, Capital (Das Kapital) is often read as an descriptive economic text, when in fact it is, among other things, a deep analysis of the ways in which Capitalism operates as an all-encompassing social form. This latter reading has enormous contemporary relevance, as it provides a new way in which to understand and thus transform society. As such, it is of particular importance to Organisers and Activists, who are my imagined audience. The essays in this publication will attempt to tease out the important lessons in Capital, based off a robust interpretation of the text. This interpretation is not without it's detractors, but my hope is that its clarity and applicability to modern phenomena will render it both plausible and illuminating. I'll attempt, where possible, to stay away from both hyperbole and unnecessary jargon. My approach, which I term Critical Activism, is influenced by the work of the social theorists commonly referred to as the Frankfurt School, who attempted to understand Capitalism in terms other than economic: cultural, political, social, psychological. Those theorists include Herbert Marcuse, Erich Fromm, Theodor Adorno, and others. It is also influenced by the work of György Lukács, and modern theorists such as David Harvey, Perry Anderson, Barbara and Karen Fields, Frederic Jameson, Diane Elson, Nancy Fraser, Michael Heinrich, and especially the late Moishe Postone. Most of all, I am indebted to a couple of key friends and comrades who helped me along this journey. Un-named, but much-loved.