Anabasis

Ten thousand Greek mercenaries marched into Persia to install a prince on his brother's throne. When that prince fell at the Battle of Cunaxa, the Greeks found themselves trapped deep in enemy territory, their Persian allies turned hostile, and their leaders betrayed and executed. What followed was an extraordinary retreat: a winter march across mountains and deserts, through hostile terrain, pursued by satraps and warlike tribes, starving and freezing, yet refusing to surrender. Young Xenophon, an Athenian aristocrat who had joined the expedition seeking glory, rose to help lead the survivors home. More than a military adventure, Anabasis is a searching examination of leadership under impossible pressure, of men discovering what they're capable of when everything goes wrong, and of the fragile bonds that hold an army together when survival demands everything. Written in the fourth century BC, it remains the oldest surviving first-person narrative of war, a foundational text that has shaped military thought from Alexander to the present day.