The year is 1993. At the US Memorial Holocaust Museum in Washington, DC, Edwin Black surveys the exhibits with his parents, both survivors of the Holocaust. The first is a Hollerith punch-card sorting machine bearing an IBM logo. “Why is this here?” he asks himself. “Did this machine help the Nazis identify and arrest my parents?” Black did more than ask the question: he sought an answer. After years of exhaustive research, he concluded that the IBM corporation facilitated the Nazi regime’s brutally efficient methods of identifying Jews and sending them to extermination camps, confiscating their assets, and automating the German war machine. These are discoveries Black reveals in his shocking book, IBM and the Holocaust.

The image of a tattooed number on the forearm of a death-camp survivor is one of the most recognized symbols of the Holocaust. Black shows that these numbers initially correlated to the IBM Hollerith punch-card system. The Nazis’ massive project of identifying, deporting, and exterminating the Jews required data processing capabilities that any modern computer system could easily supply. However, there were no such computers available to the Third Reich in the 1930s. IBM virtually monopolized the most advanced data processing technology, in the form of Hollerith punch cards and the machines to sort. Black reveals that each concentration camp had its own Hollerith department, each of which used forms to identify and track prisoners and forced laborers. These same forms were co-designed by IBM consultants specifically for that purpose. Black’s account reveals for the first time that the designation of Sonderbehandlung for a prisoner—a Nazi euphemism for extermination—was coded by the IBM machines as the number six.

How could such a prestigious, seemingly all-American firm collaborate with such a reprehensible government, a participant in arguably the most heinous crime in the history of humanity? Black’s unflattering history of IBM and its CEO Thomas J. Watson documents the corporation’s takeover of its German importing agency, Dehomag, during the hyperinflation days of the Weimar Republic. Dehomag was an acronym for Deutsche Hollerith Maschinen Gesellschaft.

Once Hitler rose to power, Nazi Germany would become second only to the United States as IBM’s best customer. Watson and IBM saw in the Third Reich not so much a threat to the world as an opportunity for unbridled profit. The relationship was mutually beneficial. One of the first challenges of the new Nazi government was the rapid and accurate identification of the Jews. IBM stepped forward to provide the means. Hitler even created a special medal, the Merit Cross of the German Eagle with Star—the highest honor that could be bestowed on a non-German—and presented it to Watson in a lavish ceremony in 1937. Germany in turn became dependent on IBM technology for its totalitarian vision of the future.

Black’s meticulous documentation reveals an undeniable fact: after the outbreak of the World War II, the IBM corporation knew the whereabouts of each of its European-leased machines, and what revenues it could expect from them. Each machine was insured and serviced monthly on site. Even though Watson returned his medal to Hitler under public pressure, he continued to micromanage the German and European operations.

In his documentation of Watson’s fight to maintain control over IBM’s German operations, Black shows just how great a stake Watson and IBM had in their business ties with the Nazis. When the German managers of IBM moved to sever ties with IBM-New York, Watson vigorously fought to maintain control, using German corporate law to his advantage. The fight was bitter, precisely because IBM’s technology was the centerpiece to the automation of the German war effort and the operation of the Nazi party. Germany had become dependent upon IBM-New York’s vast knowledge, technology, and financial support. It would have taken years for Germany to wean itself away from IBM’s systems, and Watson knew this very well, noting the profits that would accrue from a continuing relationship. He did this with the knowledge, unknown to most, of the purposes for which his machines were deployed.

When the war ended in Germany, the victorious Allies discovered just how dependent the Nazi regime had been on IBM’s Hollerith technology. Remarkably, Black demonstrates that the Allies, instead of indicting IBM, saw in these machines and their data a great opportunity to conduct a more efficient occupation of Germany and a more effective rebuilding of Europe. Instead of evidence of crimes against humanity, the machines became an essential tool in the implementation of the Marshall Plan. In this way, IBM evaded any hint of complicity in the Holocaust—at least until the publication of Black’s book.

Now, the burden of proof rests squarely with IBM. What will it do with this thoroughly documented accusation, this long-overdue indictment of corporate greed? Black’s book has done what US and international organs of justice chose not to do five decades ago.

Not to remember is to give Hitler his victory. “Never forget” is the mantra imposed upon us all by the Holocaust. Over 15 million people have visited the Holocaust Museum since Black’s visit. Surely, many of them have asked the same questions. Black has furnished them with answers.

Although its message may prove disconcerting, Black’s book succeeds in calling to justice those who may have escaped indictment in the historical record. Regardless of IBM’s response to Black’s claim, the author has undoubtedly changed the light in which we see one of United States’ most storied corporations.