The Estonian-born Wuolijoki was herself an author and leftist Member of Parliament, as well a businesswoman and Director of the Finnish Broadcasting Company, YLE.
She collaborated with Bertolt Brecht and was a friend of Maxim Gorky, and was at one point imprisoned and condemned to death for alleged treason -- charges which were later dropped.
Published last month, the book is already in its fourth printing. Tuomioja did international research for it over the past 10 years. However he was denied access to KGB archives.
Selecting Tuomioja's book from a shortlist of candidates was Professor Raimo Väyrynen, director of the Academy of Finland -- and an applicant for the directorship of the new Parliamentary Institute of International Affairs. Väyrynen and Tuomioja are fellow Social Democrats.
The non-fiction Finlandia, like the parallel prizes for literature and children's books, is worth 26,000 euros.