The long-term development of political systems over extended time periods has been somewhat neglected. More People, Fewer States examines world history through population explosion and empire size changes across 5000 years of socio-technological development, revealing three distinct phases: Runner, Rider, and Engineer empires. A careful comparative approach reveals that Old Egypt, Achaemenid, Caliphate, Mongol, and Britain each achieved remarkable yet rarely acknowledged expansions, leading to their successive record empire sizes. If identified past trends persist, a potential single world state could emerge by 4600, although environmental concerns may intervene. Focusing on population dynamics and area metrics of states, this book provides a novel framework for evaluating the growth, structure, and decline of empires. It not only illuminates ancient historical space but also ventures into future projections, making it an essential read for scholars interested in the long-term evolution of political systems.