Herodotus: The Histories

Book One, Chapters 1 - 94.

The conflict between the East and the West, according to Herodotus, was the product of a series wife-stealing incidents that dated back to Homeric times. Both had different views on whether or not this was worth fighting a war over.

Croesus, king of Lydia, brought the Greeks into political contact with the rest of the world by demanding tribute and making alliances with them. His rule was a product of domestic stasis that was fated to end, according to Herodotus. Croesus waged war with little pretext and every victory only made him desire more power: unlike his predecessors, he started constructing a navy, but abandoned the project and exerted indirect control over the nearby island.

Although he was restless to expand his territory, Croesus waged war because of his confidence in victory and determination to punish a slight Cyrus' ancestors had inflicted on his.
Meanwhile, Persian power to the East was increasing and Croesus hoped to check its expansion. No amount of preparation, however, could save Croesus from his fate. Persian camels coupled with an inopportune disbanding of his military cost him his empire.

Croesus' predecessor, Alyattes, waged war for the sake of maintaining his army. Never went out of bounds and only pillaged Milesia. "No country can produce everything it needs," Solon told Croesus, "whatever it has, it is bound to lack something. The best country is the one which has the most." War is an irrational act, according to the defeated Croesus. "In peace, sons bury fathers, but in war, fathers bury sons."

SOME BROAD THEMES:
Constructivist: a state's behavior and the outcome of wars is as much the product of the chance character and temprement of the leader. Retribution and vengeance animate the behavior of individuals and states. Any act of overweening pride inevitably leads to destruction: Croesus.
Human prosperity, for Herodotus, never lasts long in one place: Croesus.