This is a question based on the excellent Holocaust-denial post made by /u/commiespaceinvader back during a Methods Monday. I watched a documentary made by NOVA about his trial, and it seemed like a lot of his "research" was subject to confirmation bias and not conducted comprehensively. I'm wondering if he's done anything useful for this field. In addition, are there other examples of famous "alternatively-motivated historians?"
Personally i have a lack of knowledge on the work by David Irving. What i can talk about is other Holocaust research and academia. Due to battery life, this will have to be a tad limited, sorry for this.
You ask for "well-known" researchers, then i will give you three.
Starting with Hilberg, the so called "Grandfather of Holocaust studies" creating what can be deemed to be the basis of all modern holocaust research. His magnum opus "The Destruction of the European Jews" is 1273 pages.
Very noteworhy is Christopher R. Browning, famous in the field of Holocaust research, especially for his book "Ordinary Men: Reserve Police Battalion 101 and the Final Solution in Poland." What makes Browning so interesting is his work with the 101 police battalion, showing the people behind the killing. He conclude with the same fact that Hilberg does in his book, that in fact that it was 'ordinary Germans' that were the perpetrators of the Holocaust, not just SS-troops or the Einsatzgruppen. "They did not kill because they were coerced by the threat of dire punishment for refusing"^1. Browning argues that the 'ordinary Germans' became killers based on basic obedience to authority and peer preassure, not based on bloodlust or primal hatred.
Last, as you mention people that have "prevented" Holocaust research, you have the obvious name of Daniel J. Goldhagen with his, New York Times Bestseller "Hitlers Willing Executioners: Ordinary Germans of the Holocaust". This book is an indirect response to Brownings book on the Police Battalion, where Browning argues the fact that even if the perpetrators were Ordinary Germans, they did not kill the Jews out of their own will, Goldhagen argue that due to the German Phenomenon, mentioned a few lines down, the perpetrators were willing executioners. His book takes the stance that the Holocaust could only happen in Germany based on a German Phenomenon called "Eliminationist Anti-Semitism". Goldhagen argues that this was the sole motivation for the Holocaust and comes often with outlandish and overconfident statements. "With regards to the motivational cause of the Holocaust, for the vast majority of perpetrators, a monocausal explanation does suffice."^2 and “their[German people] approval[of the holocaust] derived in the main from their own conception of Jews is all but certain, for no other source of motivation can plausibly account for their actions.”^3
After Goldhagen became a massive commercial success, increasingly many scholars started writing reviews and essays explaining how Goldhagen was wrong. Hilberg goes as far as to outright dismiss the work of Goldhagen. Notable reviews and Essays regarding the book: Yehuda Bauer "On Perpetrators of the Holocaust and the Public Discourse", Hilberg "The Goldhagen Phenomenon" and Browning "Daniel Goldhagen's Willing Executioners".
Goldhagen is an important example of someone using the same sources as others (Browning) yet reaching comepletely different conclusions, although his work was dismissed by most scholars, it is an important lesson to learn from, do not only pick information that help your case.
Sources:
Bauer, Y. and Finkelstein, N. G. (1998), The Jewish Quarterly Review, Vol. 89, No. 1/2 pp. 123-126
Bauer, Y. (1997) On Perpetrators of the Holocaust and the Public Discourse. The Jewish Quarterly Review, Vol. 87, No. 3/4, pp. 343-350
Hilberg, R. (1997) The Goldhagen Phenomenon. Critical Inquiry, Vol. 23, No. 4, pp 721-728
Browning, C. (1996). Daniel Goldhagen's Willing Executioners. History and Memory, 8(1), pp.88-108
Goldhagen, D. (1996). Hitler's willing executioners. 1st ed. New York: Knopf
EDIT: Goldhagens' book is a very interesting read where he bring up case studies like the death marches, I would definitely suggest reading up on the "duel" between Goldhagen and Browning
Irving's early works including Goering and The War Between the Generals were considered scholarly and well-researched. This was a period when a lot of the first generation of postwar history was being questioned, and certain myths brought into question.
It was in the 1980s that Irving became more and more associated with Nazi apologists, emerging from his willingness to criticise the Allies. His book The Destruction of Dresden is unquestionably the result of original research, but his methodology to arrive at a casualty figure of 135,000 is highly dubious.
His trial showed this. Close analysis of his writings didn't completely discredit him, it found a tendency, increasing over time, to interpret his findings in a subjective way.
I consider AJP Taylor to be of a similar ilk, but because he's not a Nazi apologist its much less of an issue. Some of his statements, his sweeping dismissal of contentions, are astounding. This is especially so in relation to his treatment of First World War Allied commanders.