The 14,500 Polish army officers, police, gendarmes, and civilians taken prisoner by the Red Army when it invaded eastern Poland in September 1939 were held in three special NKVD camps and executed at three different sites in spring 1940, of which the one in Katyn Forest is the most famous. Another 7,300 prisoners held in NKVD jails in Ukraine and Belarus were also shot at this time, although many others disappeared without trace. The murder of these Poles is among the most monstrous mass murders undertaken by any modern government. Three leading historians of the NKVD massacres of Polish prisoners of war at Katyn, Kharkov, and Tvernow subsumed under "Katyn"present 122 documents selected from the published Russian and Polish volumes coedited by Natalia S. Lebedeva and Wojciech Materski. The documents, with introductions and notes by Anna M. Cienciala, detail the Soviet killings, the elaborate cover-up, the admission of the truth, and the Katyn question in Soviet/RussianPolish relations up to the present.

Anna M. Cienciala, a specialist in twentieth-century Polish diplomatic history and Katyn, is a retired professor of history at the University of Kansas, Lawrence. Natalia S. Lebedeva, the leading Russian historian of Katyn, is a researcher at the Russian Academy of Sciences, Moscow, who has edited other documents and published articles on Soviet-Polish relations, the Comintern, and other subjects. Wojciech Materski, the leading Polish historian of Soviet/Russian–Polish relations and Katyn, is director of the Institute of Political Studies, Polish Academy of Sciences, Warsaw.