He was born in Leipzig as a son of Stian Sanness (1880–1966) and Hanne Theodora Munthe (1882–1954). The family moved to Kristiania seven years later, and Sanness attended Kristiania Cathedral School. He joined the revolutionary group Mot Dag during this period, and was expelled from his school for protests against the 25-year anniversary of the monarchy in 1930.[1] He later declined an offer to be reentered, and finished his secondary education as a private candidate.[1] In 1940 he chaired the Norwegian Students' Society.[2]
In April 1940, Norway was invaded and occupied by Nazi Germany. Sanness learned from a Norwegian official in the government that he was on a list of people who would be arrested by the Gestapo, so he escaped to neutral Sweden. He travelled to London in 1941. Here he worked as a secretary for Arne Ording. Both Sanness and Ording had been Mot Dag members, but were now more mainstream Labour Party members. In addition to working for Ording, Sanness was involved in BBC broadcasts to occupied Norway,[1] and he was a commentator in the illegal press.[3]
Notable releases include Verden blir én 1850–1914, volume five of Aschehougs verdenshistorie released in 1955. He also published studies on the Soviet Union (Sovjetsamveldet under Khrustsjov, Bergen 1960; Some Problems in the Study of Soviet Foreign Policy, 1978), Norwegian foreign policy (Norsk alliansefri politikk?, 1978) and historiography (Norske historikere og den kalde krigen, 1984). He edited the encyclopedia Tidens leksikon, released in 1975–1976, together with Einar Gerhardsen and Odd Højdahl. He also edited the periodical Samtiden from 1964 to 1967.[1]
Sanness was fluent many foreign languages, including German, Russian, French and Spanish. He also spoke some Finnish. Since 1939 he was married to Dagny, née Goa. His wife outlived him as he died in November 1984 in Oslo.[1]
