In the 1930s, thousands of Finns emigrated from their communities in the United States and Canada to Soviet Karelia, a region in the Soviet Union where Finnish Communist migrs were building a society to implement their ideals of socialist Finland. To their new socialist home, these immigrants brought critically needed skills, tools, machines, and money. Educated and skilled, American and Canadian Finns were regarded by Soviet authorities as agents of revolutionary transformations who would not only modernize the economy of Soviet Karelia, but also enlighten its society. North American immigrants, indeed, became active participants of socialist colonization of what Bolshevik leaders perceived as dark, uneducated and backward Soviet ethnic periphery. is the first comprehensive account in English of this fascinating story. Using a vast body of documentary sources from archives in Petrozavodsk and Moscow, Russian- and Finnish-language press and literature from the 1930s, oral history interviews and secondary literature, Alexey Golubev and Irina Takala explore in depth the Karelian fever among Finnish Americans and Canadians, and the lives of immigrants in the Soviet Union, their contribution to Soviet economy and culture, and their fates in the Great Terror.