On 30 November 1939, Soviet bombers unloaded their bombs on Helsinki, the capital of Finland. Stalin's ultimatum, demanding the cession of huge tracts of territory as a buffer zone against Nazi Germany, had been rejected by the Finnish government, and now a small Baltic republic was at war with the giant Soviet military machine. But this forgotten war, fought under brutal, sub-arctic conditions, often with great heroism on both sides, proved one of the most astonishing in military history. Using guerrilla fighters on skis, even reindeer to haul supplies on sleds, heroic single-handed attacks...