[1]: xxiv At the end of 1945, Stalin ordered the NKVD (the People's Commissariat of Internal Affairs—a precursor to the KGB) to investigate the circumstances of Hitler's supposed death and to reconstruct the last days of April 1945 inside the Führerbunker.

People's Commissar Sergei Kruglov was in charge of this investigation, while the actual writing of the final report was done by the security service officers Fyodor Parparov and Igor Saleyev.

[1]: x  For instance, the NKVD held Linge in a solitary cell crawling with bugs and subjected him to repeated whippings and other humiliating tortures.

Researchers from the Institute for Contemporary History in Munich, including Matthias Uhl and Henrik Eberle, "discovered" the report in the Communist Party Archives[2] that became The Hitler Book in 2005.

Furthermore, the work is based heavily upon firsthand interviews with Linge and Günsche that were conducted under duress and inhumane conditions, thereby undermining the reliability of much of the information.

[6] The review by Publishers Weekly reminded readers that the two aides who provided the content for the book "appreciated the [Soviet] regime's need to present Hitler as a degenerate, drug-addicted tool of German imperialist capitalism.