[1] In 1972 he led the county chapter of Ja til EF, the organization campaigning for "Yes" in the 1972 Norwegian European Communities membership referendum.
[1] He helped found the Rafto Foundation for Human Rights, chairing its board for ten years.
[1] He authored biographies on Vebjørn Tandberg (together with Helmer Dahl), Rolf Berntzen and Lothar Lindtner (with Alf H. Madsen), and Hilmar Reksten.
[1] Other important books are Sea Transport and Shipping Economics (1958), Industriens historie i Norge (1969, with Gunnar Christie Wasberg) and I fartens, kraftens og velstandens epoke (1977).
Svendsen also won an Hedda Award and was a Knight, First Class of the Royal Norwegian Order of St.