In my book-length dissertation, Emerging Technologies: Implications and Prospects of their Proliferation, I advance a comparative historical account of the puzzling temporal variation in the proliferation of emerging technologies from the 1940s and 50s to the present day. My dissertation addresses the question: under what conditions do dual-use emerging technologies proliferate in the international system? I investigate the likelihood of the proliferation of three emerging technologies: artificial intelligence, robotics, and cyber. I select these three emerging innovations based on their date of discovery in the 1940s and 50s and analyze the trajectories taken by states and the private sector. I draw attention to two neglected components in the literature regarding the spread of these technologies, including the pathways of technological acquisition, namely foreign acquisition or indigenous development, and the role of international organizations in technological governance. In brief, I argue that both the pathways of technological acquisition, whether through foreign acquisition or indigenous development, and the degree of transparency and monitoring by international institutions have significant consequences for the proliferation of emerging technologies. I find that artificial intelligence is the least likely technology to proliferate, robotics is the likely technology to proliferate, and cyber is the most likely technology to proliferate based on these neglected factors. Distinct from the conventional international security scholarship, my dissertation book-length project offers three novel contributions. First, existing literature primarily focuses on military technology innovation, which often operates from a state-centered lens. However, such an approach misses out on the significant role that nonstate actors in the private sector play in technological proliferation. Second, the definition of emerging technologies lacks consensus among scholars and policymakers as it is an ambiguous concept. My work sheds insights on the conceptual understanding of ‘emerging technologies,’ shows how to operationalize emerging technologies, and facilitates empirical research into the topic for academia and policy. I leverage a multi-method approach (e.g., original datasets, 25 semi-structured elite interviews in Hamburg, Berlin, and Silicon Valley, and case studies). Third, I seek to go beyond the literature by examining neglected emerging innovations that largely possess ‘non-kinetic’ effects, such as financial and electoral disruptions.