Lappilaisten sotakokemuksia 1939–45 (SKS 1999) Lähteenmäki earned the reward of the Väinö Tanner Foundation (2000), as well as the President Urho Kekkonen's 70th Anniversary Fund's prize from her research Kalotin kansaa.
Kannaksen rajamaa ja poliittiset murtumat 1911–1944 (SKS 2009) deals with Finland's and Russia's/Soviet Union's vulnerable border area Terijoki in the Karelian Isthmus from historical perspective.
For example, when writing about the War of Lapland Lähteenmäki notes that Finnish military leaders agreed to surrender Lapland lightly to German warzone without giving a thought for fact that civilians were left to dangerous border areas (Helsingin Sanomat 29.3.1999, Suomen Kuvalehti 13.8.1999).
Lähteenmäki graduated as baccalaureate from Sodankylä upper secondary school (1977) and studied at the University of Helsinki, Finnish history as her primary subject.
She worked as an assistant and lecturer of history in 1991-2001, and as professor in 2003 and 2007 at the University of Helsinki as well as Senior Researcher in the Finnish Academy in 2001-2009.