The fourth book covers the thrilling actions of the Spartan king Agesilaus against the Persians in Asia, as well as his return to Greece to confront the most important cities (Thebes, Athens, Corinth, Argos) that banded together against Sparta, due to the abundance of corrupting Persian gold.

The fifth book describes all the events that led to the shameful Peace of Antalcidas (387 BC), during which, due to the Spartan desire for power, almost all cities in Asia Minor and many islands were ceded to the Persians. The Spartans, absolute rulers in the Greek world, resort to arbitrary actions against cities in the Peloponnese, Chalcidice, etc., but face the resistance of the Thebans and Athenians.

All of this leads to the hegemony of Thebes (371 - 362 BC) under Pelopidas and Epaminondas, which Xenophon will outline in his last two books, VI and VII.

[Excerpt from publisher or edition presentation text]