the association between the war against the Soviet Union and the Holocaust, while Guttenplan described their "distortion" of Mayer's opinions as "disgraceful", noting also that Arno Mayer's book opens with "A Personal Preface" telling of his own hair-raising escape from Luxembourg and occupied France, and of the fate of his grandfather, who refused to leave Luxembourg and died in Theresienstadt. Such personal bona fides didn't prevent the Anti-Defamation League from including Mayer in its 1993 "Hitler's Apologists: The Anti-Semitic Propaganda of Holocaust Revisionism", where his work is cited as an example of "legitimate historical scholarship which relativizes the genocide of the Jews." Mayer's crime is to "have argued, with no apparent anti-Semitic motivation"—- note how the absence of evidence itself becomes incriminating—- "that though millions of Jews were killed during WWII, there was actually no premeditated policy for this destruction." Reviewers criticized Mayer's account of the Holocaust as emphasizing Nazi anti-communism too much at the expense of antisemitism. Israeli historian Yehuda Bauer alleged that <blockquote> when a Holocaust survivor such as Arno J. Mayer of Princeton University ... popularizes the nonsense that the Nazis saw in Marxism and bolshevism their main enemy, and the Jews unfortunately got caught up in this; when he links the destruction of the Jews to the ups and downs of German warfare in the Soviet Union, in a book that is so cocksure of itself that it does not need a proper scientific apparatus, he is really engaging in a much more subtle form of Holocaust denial. He in effect denies the motivation for murder and flies in the face of well-known documentation.</blockquote> Another controversy concerned what Robert Jan van Pelt termed Mayer's "well-meant but ill-considered reflection on the causes of death in Auschwitz". Mayer had concluded as follows: "certainly at Auschwitz, but probably overall, more Jews were killed by so-called 'natural' causes than by 'unnatural' ones." This conclusion removed the lingering restraints—if any actually remained—preventing David Irving from publicly announcing he did not believe the gas chambers at Nazi camps like Auschwitz existed. Guttenplan termed Mayer's musing on differences between 'natural' and 'unnatural' deaths, even if the terms were used in quotation marks, "indefensible". Holocaust deniers have often quoted out of context Mayer's sentences in the book: "Sources for the study of the gas chambers are at once rare and unreliable". As the authors Michael Shermer and Alex Grobman have noted, the entire paragraph