4 ideas
In 1999 he is the only subject successfully revived. His physician, Dr. Geiger, has him keep a diary to rebuild his memory, and the diary gradually reveals that he really did kill Zaretsky, the neighbor whose denunciation led to the arrest and death of the father of Anastasia, the woman he loved.
Textbooks keep wars and revolutions but lose the smell of a dacha veranda, the sound of a particular street, and the taste of a childhood pie. These details disappear when the people who lived them die. Innokenty's diary treats these particulars as the real substance of a vanished era, because that is where the lived texture of an epoch is recorded.
The novel rejects the idea that the revolution or the camp regime caused people's cruelty. Historical upheaval only gives existing sin room to show itself, so every informer, guard and killer answers for their own acts. That includes Innokenty's murder of Zaretsky, which he cannot excuse by pointing to the times.
A man lifted out of one era and set down in another sees what natives of both have normalized. He notices the losses, the new noise and indifference, and also the continuities, such as an aged camp torturer still living quietly in 1999. Because his sense of time is broken, he can weigh the past and present against each other without taking either for granted.