Despite their commonalities, the Arab Gulf States have started economic diversification from different settings and against different political backgrounds. This book applies a multi-method approach including Qualitative Comparative Analysis (QCA) to highlight their heterogeneous economic development trajectories and to compare them to other major oil exporters. From a political economy perspective, it demonstrates how neoclassical economic theory fails to grasp the underlying mechanisms of their development. The research design of this study is tailored to small and medium-sized samples with special characteristics. As such, it offers new opportunities for comparative studies not only of this region but also of other specific samples of countries from a wider perspective of heterodox economics.