Stephen F. Cohen, an eminent historian whose books and commentaries on Russia examined the rise and fall of Communism, Kremlin dictatorships, and the emergence of a post-Soviet nation in the 21st century, died Sept. 18 at his home in Manhattan. He was 81.

A professor emeritus of Russian studies at Princeton University and New York University, Cohen chronicled a Russia of sweeping social upheavals and the passions and poetry of a people who had endured a century of wars, political repression, and economic hardship.