The character of Dr. Vogel was loosely based on Dr. Josef Mengele, S.S. officer and physician in the Auschwitz concentration camp, who injected dyes into victims' eyes and performed other "experiments", such as the ones described in one of the scenes in this movie.
Dame Helen Mirren, in her role as Rachel, was required to speak some dialogue in Russian, and although her father was a Russian diplomat, she did not speak the language in childhood. However, the lines she speaks in this movie, perhaps fully or partially memorized phonetically, are nearly flawlessly articulated and quite credible as native Russian speech.
The screenplay for this movie was featured in the 2008 Blacklist; a list of the "most liked" unmade scripts of the year.