Chapter 3 focuses on the interactions between various empires and civilizations in Eurasia and North Africa from 500 B.C.E. to 500 C.E. It covers the significant dynamics of the Persian and Greek empires, the rise and fall of the Roman and Chinese empires, highlights the political fragmentation in India, and reflects on the enduring legacies of these second-wave empires. Key themes include the impact of warfare, cultural exchange, the evolution of citizenship, and the eventual collapse of these vast empires due to various internal and external pressures.