I've read Sofi Oksanen book before seeing the film and for me that's obvious that we have here a great film based on a great book. Usually the historic event crush individual lives and destinies, but sometimes is really amassing how peoples can react so different and how unexpected individual desires mixed up with historical event can generate dramas.
This film also remembered me another one, a Romanian one, "Somewhere in the East", made after Augustin Buzura's novel "Fetele tacerii", part of the subject being related.