Gulag: A History, by Anne Applebaum.  (New York: Anchor Books, 2004.)
This Pulitzer Prize winner is the authoritative history of a long, horrifying chapter in Russian history.  Exhaustively researched and brilliantly distilled.  Not easy reading but a staple for every library.

Surviving Russian Prisons: Punishment, Economy, and Politics in Transition, by Laura Piacentini.  (London & New York: Routledge, 2013.)  A British scholar’s intrepid investigation into the day-to-day reality of life in Russian prisons.

Gulag Voices: An Anthology, edited by Anne Applebaum.  (New Haven & London: Yale University Press, 2011.)  A collection of the poetry and memories of gulag survivors.  The voices are vivid, humble, shocking, wounded, and deeply courageous.

The Other Side of Russia: A Slice of Life in Siberia and the Russian Far East, by Sharon Hudgins.  (College Station: Texas A & M University Press, 2003.)  Hudgins and her husband were among the first Americans to live and work in the Russian Far East after the break-up of the Soviet Union.  Her lively account of her personal adventures and her warm, sensitive, and acutely observed descriptions of Siberian cultural life make for terrific reading.  An engaging and illuminating journey into the heart and soul of the Russian Far East.

Midnight in Siberia: A Train Journey into the Heart of Russia, by David Greene.  (New York: Norton, 2014.)  Crossing Russia on the Trans-Siberian railroad, journalist David Greene meets ordinary Russians and lets them speak in their own voices about their country and their lives.  Candid and affecting.

The Last Man in Russia: The Struggle to Save a Dying Nation, by Oliver Bullough.  (New York: Basic Books, 2013.)  A look at the decline of Russian society through the tale of a lone dissident Christian Orthodox priest.  Passionate and original.