For so many of us who lived through a large chunk of the Cold War, the Soviet Union was a deep and convoluted mystery. As Winston Churchill put it, “It is a riddle, wrapped in a mystery, inside an enigma.”

Stalin’s Daughter: The Extraordinary and Tumultuous Life of Svetlana Alliluyeva (Rosemary Sullivan) is a fascinating and deeply-researched biography of Svetlana Alliluyeva, the daughter of murderous Soviet dictator Joseph Stalin. Sullivan’s multitude of interviews and scholarly research gives readers a rare look inside life in the Kremlin and the Soviet Union, as Stalin ruled with an iron hand. It is quite the tragic picture.

At times plodding, overloaded with minutia, and opinionated about Svetlana’s life choices, the book is still worth the effort. The reward is a new understanding of what it’s like to live through generations of repression, as nearly all Soviet citizens did. Sullivan also delivers a powerful psychological study of a woman who had to come to terms with the fact that the father she once idolized was really a mass murderer.

Sullivan’s book is a real gift for anyone who wants to unravel the great riddle of the Soviet life.