The German firm of J. A. Topf and Sons was one of the countless, medium-sized family-owned manufacturing businesses that formed the backbone of post-Industrial Revolution Europe. Founded in 1878 in the town of Erfurt, near Weimar, the firm specialised in brewing and milling, expanded into war vehicles and grenades in the First World War, and then switched gear to take advantage of a growing business opportunity: cremation.

The company was a model of its kind, adhering to strict German regulations and burning one body at a time in its ultra-efficient ovens.

In the 1930s, the firm, by now run by the brothers Ludwig and Ernst Wolfgang Topf, was equally swift to adapt to the advent of the Nazis. When a concentration camp was opened at nearby Buchenwald, Topf was ideally placed to pitch for the cremation ovens needed to dispose of the sudden surge in corpses there. As Karen Bartlett explains in her admirably revealing new history of the firm, nobody at Topf, from top to bottom, ever seemed to query exactly why so many of their products were suddenly needed. Talk about only obeying orders — in this case for crematoria. Not only that but the firm was assiduous in seeking to make bigger and better ovens to cope with the ever-increasing demand, winning the order for new equipment at Auschwitz. A key figure was its engineer, Kurt Prüfer, a Nazi party member who liaised enthusiastically with the SS and even demanded bonuses.

After the war ended, everyone concerned denied all knowledge of the foul use their ovens had been put to, but Bartlett produces plenty of evidence to place the Topfs, Prüfer and others squarely at the scene of the crime. As with all Holocaust histories, the detail can be distressing but demands to be read.

The story did not end in 1945. Ludwig Topf committed suicide on the eve of interrogation by the Americans, but Ernst Wolfgang spent decades trying to clear the family’s name, unsuccessfully.

This is a parable of 20th-century Germany and its relationship with the Nazis: first acquiescence, then full-scale involvement, and finally denial.

The only bright spot in this grim story is provided by Hartmut Topf, a cousin of the brothers, who fought for years against stiff opposition to turn the disused Topf headquarters into a Holocaust memorial. Otherwise, the Topf story is a perfect example of what Hannah Arendt so memorably described as the banality of evil.

Robert Low is consultant editor of Standpoint magazine