This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book helps to engage in knowledge accumulation by systemically researching structural transformations, especially during unipolar and post-unipolar periods. It shows how to discover new findings by observing probabilistic outcomes vis-a-vis the power configurations of a system and assessing how this can contribute to practical policy formulation or have policy implications. The book introduces an original conceptualization of nonpolarity that may contribute to the development of a robust theoretical model that can enrich the political and scientific study of polar structures and world/global political system(s). It discusses the methodological design of research project, fusing qualitative, semi-quantitative and analytical methods. The book also addresses systems analysis, political history, selective process-tracing, and the operationalization of the case studies. It concludes the case studies by addressing the European System from the 1500s and how its expansion provides for the formation of the Global Political System.