The term radical, as used by Kelley, describes political movements that seek to replace the current governmental and societal system mostly or entirely. Specifically, Kelley writes about radical leftist politics—that is to say, radical socialist and/or communist politics. Radical politics are in opposition with mainstream political ideologies such as liberalism, which seeks to make incremental change to systems and institutions.

Communism is a political ideology that extensively critiques the bourgeoisie, a term from French that describes the upper classes who own the means of production. The means of production are things like the machines in factories, land, and the work of laborers. Communist ideology holds that workers (the proletariat), rather than the bourgeoisie, should own the means of production. The adjectival form of bourgeoisie is bourgeois. As a Marxist historian, Kelley writes about how Black radicals throughout history have critiqued the bourgeoisie, including the Black bourgeoisie, for their perceived inability to create meaningful change in politics and society.

Vanguardism is an element of Leninist Communist politics. It is a strategy where the vanguard, or class-conscious members of the working class or proletariat, form organizations to spread knowledge of communism and build support for the movement. The term comes from military strategy where an advance force, or vanguard, would go in before the rest of the army to prepare the terrain for an action.