From 1935 to 1942 he served as the head of the English Department at the University of Scranton, publishing widely in scholarly and popular journals.
[independent source needed] App laid out eight axioms, or what he described as "incontrovertible assertions", about the Holocaust in his 1973 pamphlet The Six Million Swindle: Blackmailing the German People for Hard Marks With Fabricated Corpses, which denied the existence of gas chambers and tried to show it was impossible for six million Jews to have been killed.
[9][10][2] In February 1976, App published an article "The Sudeten-German Tragedy" in Reason magazine, criticizing the post-World War II expulsion of the Sudeten Germans as "one of the worst mass atrocities in history.
[independent source needed] App also published A Straight Look at the Third Reich, a defense of Nazi Germany, and The Curse of Anti-Anti-Semitism, arguing that the entire Jewish community is responsible for the death of Christ.
[2] App's work inspired the Institute for Historical Review, a Holocaust denial center in California, founded in 1978.