On November 4, 2022, a Finnish-Lithuanian history colloquium was organized, the theme of which was War and Society in the Baltic Region. The colloquium discussed the various effects of the war on society in the light of the history of Finland and Lithuania. The temporal focus was the first half of the 20th century, but several presentations also dealt with the post-war aftermath, especially traumas that still extend to the present day. Other central themes were the interweaving of war and diplomacy, preparation for crisis situations, reactions in society caused by the outbreak of war, and official and unofficial commemorations of wars. The scientific articles in this compilation are based on the presentations given at the colloquium.