[1][2] In the 1950s, he discovered 70 unknown letters by Hamsun and embarked on a life-long project to gather, study, and publish the late author's correspondence.

[3] He did so as Torger Thompson Professor in the University of Wisconsin-Madison's Department of Scandinavian Studies, an institution for which he was the "guiding force" from the early 1960s until his retirement in 1991.

[7] In 1959, with the blessing of Signe Frydenlund, Næss published the previously unknown letters between Hamsun and her father in the journal Edda.

That same year he received a Fulbright Scholarship to support a visiting appointment in the Scandinavian Studies Department at the University of Wisconsin-Madison.

At the State Historical Society, he found four letters between Hamsun and Rasmus B. Anderson, founder of Næss' department.

By the early 1980s, Næss' work in the United States, Norway, Sweden, Denmark, Germany, and elsewhere had yielded a collection of more than 2000 letters.