The first collection of Russian documents in English on the Soviet massacre of Polish prisoners of war in 1940 and the fifty-year cover-up that followedThe 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 Tver—now 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/Russian–Polish relations up to the present.