Donald Kagan (/ˈkeɪɡən/; born May 1, 1932) is an American historian and classicist at Yale University specializing in ancient Greece, notable for his four-volume history of the Peloponnesian War. He formerly taught in the Department of History at Cornell University. At present, Kagan is considered among the foremost American scholars of Greek history.

Books in order of publication:

The Great Dialogue: A History of Greek Political Thought from Homer to Polybius – 1965

The Outbreak of the Peloponnesian War – 1969

The Archidamian War – 1974

The Peace of Nicias and the Sicilian Expedition – 1981

The Fall of the Athenian Empire – 1987

Pericles of Athens and the Birth of Democracy – 1991

On the Origins of War and the Preservation of Peace – 1995

While America Sleeps – 2000

The Heritage of World Civilizations – 2000

The Western Heritage – 2003

The Peloponnesian War – 2003

Thucydides: The Reinvention of History – 2009

Men of Bronze: Hoplite Warfare in Ancient Greece – 2013