This book purports to critically analyze Wallerstien’s world-systems theory, to test its strengths and weaknesses and establish its reliability as an international relations theory, thereby reviving Marxism in world politics. The study employs a qualitative research method to go deep into the underlying logic of the theory. In an endeavor to tackle the matter at hand, five criteria of analysis are employed to examine the merits and demerits in specific areas of the theory. This involves looking at the structure of the theory, the period of the emergence of capitalism, the unit of analysis, the coherence of the arguments and processes of the theory and the reliability of the world-systems theory in contemporary world politics. The five criteria used proved that the theory is reliable when used to explain three themes in world politics,these are global inequality, dependency and sovereignty.