"Throughout the human experience people have read history because they felt that it was a pleasure and that it was in some way instructive," says Donald Kagan. "Without history, we are the prisoners of the accident of where and when we were born." Known to his students as a "one-man university," Kagan has illuminated the history of the ancient Greeks for thousands of students and readers.

Kagan began studying the classics while he was an undergraduate at Brooklyn College. "I felt drawn to these remarkable people," says Kagan, who saw a "tragic spirit" in the ancient Greeks in the way they approached mortality. "They faced the fact that death would come, and it was terrible, but the fact that death would come did not mean that what we did while we were alive was unimportant."

Kagan's best known work is his monumental four-volume history of the Peloponnesian War. He admires Thucydides, the original historian of that war, and credits him with changing how history is written. "Thucydides stood on the edge of philosophy. He was sufficiently a historian to feel compelled to establish the particulars, to present the data as accurately as he could, but he was no less, and perhaps more, concerned to convey the general truths that he had discovered."

"It's not an accident I spend most of my life reading Thucydides. Most people who are interested in history start with him," continues Kagan. "Herodotus is first, but there's a continuity between Thucydides and the way he carried out his work and serious historians afterwards."

Born in Lithuania in 1932, Kagan was the first in his family to attend college, earning his master's degree in classics from Brown University, and his doctoral degree in history from Ohio State University in 1958. He holds honorary Doctor of Humane Letters degrees from the University of New Haven and Adelphi University. Before coming to Yale in 1969, Kagan taught at Pennsylvania State University and Cornell University. From 1988-93, Kagan served as a member of the National Council on the Humanities. He has won numerous awards and fellowships, including four teaching awards at Cornell and Yale. President George W. Bush presented him with a 2002 National Humanities Medal.

Kagan's recent books include Pericles of Athens and the Birth of Democracy (1991), On the Origins of War and the Preservation of Peace (1995), While America Sleeps: Self-Delusion, Military Weakness, and the Threat to Peace Today (2000, with Frederick W. Kagan), and The Peloponnesian War (2003), a one-volume history of the war. He also has published numerous articles and commentary for the Wall Street Journal, the New York Times, and the Public Interest. Kagan lives in Hamden, Connecticut, with his wife, Myrna.

- Amy Lifson