A troubling family history can cast a shadow over one's life, no matter how brilliant that life may be. Martin Davidson is a graduate of Oxford, the commissioning editor for history and business programming for the BBC, and a producer of documentaries for A&E and the History Channel. He was well into his career when in 1992 he found he had a ghost to chase --- that of his grandfather, the jovial dentist who, he learned, was a fanatical Nazi, one of the early followers of Hitler and a man well-rewarded for his party loyalty.

THE PERFECT NAZI is Davidson's personal documentary, a disturbing look at the mask of banality and human feeling covering a distorted, sin-ridden countenance.

Born in 1906, Bruno Langbehn was a young man studying for dentistry when he became obsessed with the philosophy of Adolf Hitler. As Davidson remarks, it was a "journey from teenage fanatic to Third Reich perpetrator." During the early days of Bruno's captivation with Nazism, he was spurred by his reading of Mein Kämpf in which the Fuhrer-to-be made it clear that he was chosen to rid the world of the scourge of Judaism. The young man was able to deepen his involvement with Hitler's cause by participating in rallies in which communists and other enemies of the Reich-to-be were called out and savagely beaten. By 1937 he had become a commissioned SS lieutenant proud of his racial classification --- Aryan and "predominately Nordic" --- and his status as alter Kämpfer, someone who had joined the movement in its inception.

As Davidson notes, Bruno's desire to be part of the SS "placed him at the crux of the Third Reich's crucial transformation from authoritarian fascist dictatorship to fully fledged Nazi state, premised on racial exclusion and licensed international aggression." The two major tenets of Hitler's mad worldview were that all of Germany's woes were caused by "international Jewry" and that Germany had a God-given right to lebensraum.

Though Davidson had a meager paper trail and will probably never be able to establish exactly which evils his grandfather perpetrated, and though Bruno was one of many dedicated Nazis who upheld the cause and later denied it, the book is significant for its grimly determined unmasking of evil. After the war, Bruno was a personal "hitler" to his family, causing one of his daughters, Davidson's mother, to flee to Scotland. He retired cautiously to Berlin, lived comfortably off the post-war boom, and took solace, it seems, in the Cold War struggle against the communist menace that he and his cohort had so despised. One incident is recorded of Bruno physically recoiling when he encountered his granddaughter's date, a man with obvious Jewish features, so it's clear that to the last he was viscerally anti-Semitic.

For reasons of his own, Bruno chose to be buried in an unmarked grave. Perhaps that was his only admission of guilt after all the implied denials and secret pride he evinced regarding his service to his country, including his insistence later in life that Hitler had been no different from Churchill in his desire for territorial expansion. Davidson states that Bruno had "worked all his early adult life to bequeath to his children ...a world without Jews." And he opines, "The rise of Nazism had depended on men like Bruno," who could live out a mundane existence and quietly convince others of their harmlessness, yet who, underneath, were unquestioning zealots with a thirst for blood, conquest and, ultimately, genocide.