Denying History: Who Says The Holocaust Never Happened and Why Do They Say It? by Michael Shermer and Alex Grobman University of California Press 330 pp, $17.95 To explain why the holocaust never happened, here are some guidelines: Attack the perceived inconsistence of 'exterminationist' rivals while remaining non-committal about your own position. Declare that debate over a single issue - like whether Nazis always planned on genocide - calls into question whether genocide happened at all. Ignore facts. Speak only about what isn't known. Disregard eyewitnesses and anyone with numbers tattooed on the arm. Denying History dismembers the hidden world of Holocaust revisionism. The authors: Skeptic magazine founder Michael Shermer and historian Alex Grobman, remind us the past is not entirely negotiable. Their book offers a crash course in dialectics, a rogue's gallery of deniers, and refutation to claims the premeditated Nazi genocide of six million Jews is history's greatest hoax. Good historians can uncover and explain the past with provisional certainty - if they account for personal and cultural bias. Historical debates are won with converging evidence, logic, probability, peer review, and open discussion. Such methods consistently prove the holocaust was real. Only details might be up for grabs, which deniers expertly manipulate to undermine entire events. Sherman and Grobman call this snapshot fallacy, a tool holocaust revisionists use to sculpt death camps where genocide never took place. Readers are led inside the Institute for Historical Review, the leading center for Holocaust denial and anti-Semitic publishing. It considers its enemies to be the Anti-Defamation League, Wiesenthal Center, and Alan Dershowitz. In 1980, the Institute for Historical Review offered $50,000 to anyone who could prove Jews were gassed at Auschwitz. When holocaust survivor Mel Mermelsein succeeded, he had to bring the Institute to court for the money and was awarded an additional $40,000 for personal suffering. Courtroom verdicts mean little to revisionists motivated by personal interest. The IHR website is still in business, calling Elie Wiesel a false witness to the Holocaust, warning of Israel's impending attack on Iran, and highlighting articles by American congressmen Paul McClonskey and Pat Buchanan. Nothing is more dangerous than turning a back to the world of deniers. Shermer and Grobman set the example by facing revisionists in the flesh. The following are regulars at the Institute for Historical Review: Veteran denier Mark Weber was found by the authors to be personable, bright, and accepting of a society ordered through violence and deceit. He sees no double-standard in holding these views while calling Jews "the traditional enemy of truth". More legendary is David Irving, considered by the writers of Denying History to be the most sophisticated of revisionist historians. He has performed verbal acrobatics to prove the German word for extermination: ausrotten, appearing in many Nazi reports, only meant emigration. English by birth, the authors reveal Irving worked in a German steel factory after the war. There he learned about the fire bombing of Dresden, decided to write, and eventually fell in with the "magic circle" of Hitler's former associates. Donning psychologist robes, Sherman and Grobman posit Irving became overly-sympathetic to the German subjects he met, letting Hitler's war become his own. "Without Hitler the State of Israel probably would not exist today," says Irving. "To that extent he was probably the Jews' greatest friend." Irving has been banned from Canada, Australia, New Zealand, Italy, South Africa and Germany. In 2000 he lost a defamation suit he filed against Deborah Lipstadt and Penguin publishers for accusing him of Holocaust denial. A Vienna state court recently sentenced him to three years in prison on the same charge. The "Pope of Revisionism" is Robert Faurisson. He attacks gas chambers - or evidence they were genocidal. For all his writing and activism, Faursson has been fired, beaten, convicted, fined, barred from French government, and helped to inadvertently enact the Fabius-Gayssot law, which makes contesting crime against humanity a criminal offense. Michael Shermer met him in a hotel room, where Faurisson demanded "just one proof" that Nazi gas chambers were murderous. Shermer asked: "What would you consider proof?" Faurisson had no answer. Bradley Smith got interested in Holocaust revisionism after reading Faurisson's "The Problem of the Gas Chambers". He creates clashes about the veracity of the holocaust on college campuses. Smith says: "The politically correct line on the Holocaust story is, simply, it happened. You don't debate it." Shermer and Grobman disagree. "The Holocaust story has been debated for fifty years," they write. "But by historians using the accepted rules of evidence." For Smith, the discovery that some camps didn't have gas chambers "calls into doubt all accounts of gas chambers and gassing in all camps, including Auschwitz". That's a case of snapshot fallacy. Why do people revise the holocaust? "Running through all denier literature - books, articles, editorials, reviews, monographs, guides, pamphlets, and promotional materials - is a fascination with Jews and everything Jewish. No issue of the Journal of the Historical Review fails to contain something on Jews." By altering the holocaust, deniers rip the fibers of Jewish history and identity. What follows are conspiracy theories "and a hint that Hitler should have finished the job". That means revisionists rewrite the Jewish past to attack the Jewish present. Proof is Iran's President Mahmoud Ahmadinejad - no stranger to the work of David Irving. He ordered an international conference to revise the Holocaust. According to the European Jewish Press, head of the Islamic Journalists, Mehdi Afzali said: "We will invite those who believe in the imposed version as well as all those who have spent years of their lives in the study of documents related to the Holocaust and have come to the conclusion that the history books in schools and universities do not correspond to the truth." Possible conference guests included racist Horst Mahler - former Red Army Faction terrorist, gas death denier Robert Faurisson, and Arthur Butz - author of The Hoax of the Twentieth Century. It was eventually held in central Iran by the Isfahan office of the Supreme Leader of the Islamic Revolition.The Iranian state run news agency Mehr, reported the conference was organized by Bassij, a branch of the Islamic Revolutionary Guards Corps. Attending were students and professors of Isfahan University. Hamshahri, Iran's largest newspaper, has since orchestrated a holocaust denial cartoon competition. Revisionists are creating extremism. Without more Shermans and Grobmans to check their lies, in the hands of an Ahmadinejad, the extremist denial of history will lead to terror.