The main purpose of this chapter is to provide an overview of the theoretical tools used to conduct the analysis in the rest of the book: Marxism and the neo-Gramscian theoretical perspective. The neo-Gramscian theoretical perspective was developed by Global Political Economy (GPE) theorist Robert Cox in the early 1980s. Cox makes an important distinction between ‘problem-solving theory,’ which supports the status quo, and ‘critical theory,’ which explores contradictions that could lead to social change. Cox designed the neo-Gramscian theoretical perspective as a system-critical analytical tool that he aimed to use in ways that aid those involved in emancipatory projects. Key features of the original neo-Gramscian perspective, which is also known as the Method of Historical Structures (MHS), are described in this chapter, as are the modifications made to it by one of Cox’s colleagues, Timothy Sinclair. Given the urgency of the widespread ecological breakdowns we currently face, a further modification is made to Sinclair’s adjustments (the MHS Redux) in order to explicitly incorporate the Biosphere as an analytical category (the MHS Forces Redux II). This chapter of the book also provides brief overviews of Marx and Engels’ understanding of capital as self-expanding value, and of Andreas Malm’s concept of ‘fossil capital.’ In addition, several important concepts developed by the Italian Marxist, Antonio Gramsci, are defined because they are also used in the analysis in the rest of the book. These concepts include hegemony, war of position, trasformismo, and passive revolution.