The epilogue of the tumultuous saga of General Motors during the New Deal and Nazi era is still being written. In 1974, a generation after World War II, the company's controversial history was resurrected by the US Senate Judiciary Committee's subcommittee on Antitrust and Monopoly. What did GM know - and when? GM and Opel's collusion with the Nazis dominated the opening portion of the subcommittee's exhaustively documented study, which mainly focused on the company's conspiracy to monopolize scores of local mass transit systems in the United States. The report's author, Judiciary Committee staff attorney Bradford Snell, used GM's collaboration with the Third Reich as a moral backdrop to help explain the automakers' plan in more than 40 cities, to subvert popular, clean-running electric public transit and convert it to petroleum-burning motor buses. The Senate report, titled American Ground Transport, was released shortly after the Arab-imposed 1973 oil shock - and it accused GM of significantly contributing to the nation's petroleum woes through its mass-transit machinations. GM had been convicted in 1949 of leading a secret corporate combine that funded a front company called National City Lines that systematically replaced electric trolleys with oil-guzzling motor buses across America. After Snell's report was presented, GM immediately went on the counterattack, denying Snell's charges about both its domestic conduct and its collusion with the Nazis, and demanding that the Senate Judiciary Committee cease circulating its own report. That, of course, did not happen. But following the release of the Snell report, the automaker then created its own 88-page rebuttal report titled, "The Truth About American Ground Transport," whose entire first section, as it turns out, had nothing to do with American ground transport. It was headlined: "General Motors Did Not Assist the Nazis in World War II." Thus, GM's involvement with Nazi transportation in Germany juxtaposed with its conspiracy to convert electric mass transit at home became inextricably linked by virtue of the Senate's investigation, the company's own rebuttal and the compelling historical parallel between the company's conduct in the United States and its conduct in Germany. GM further demanded that the Senate never permit its own report, American Ground Transport, to be distributed without GM's rebuttal attached. The Senate agreed - a rare move indeed. Snell, however, labeled the GM rebuttal a document calculated to mislead historians and the public. Yet another generation later, in the late 1990s, GM's collaboration with the Nazis was again resurrected when Nazi-era slave laborers threatened to sue GM and Ford for reparations. At the time, a GM spokesman told a reporter at The Washington Post that the company "did not assist the Nazis in any way during WWII." The effort to sue GM and Ford was unsuccessful, but both Ford and GM, concerned about the facts that might come to light, commissioned histories of their Nazi-related past. In the case of Ford, the company issued its 2001 report, compiled by historian Simon Reich, plus the original underlying documentation, all of which was made available to the public without restriction. Ford immediately circulated CDs with the data to the media. Researchers and other interested parties may today view the actual documents and photocopy them. The Reich report concluded, among other things, that Ford-Werke, the company's German subsidiary, used slave labor from the Buchenwald concentration camp in 1944 and 1945 and functioned as an integral part of the German war machine. Ford officials in Detroit have publicly commented on their Nazi past, remained available for comment, apologized and have generally helped all those seeking answers about its involvement with the Hitler regime. As for GM, it commissioned eminent business historian Henry Ashby Turner Jr. in 1999 to conduct an internal investigation and report his findings. Turner, author of several favorably reviewed books, including German Big Business and the Rise of Hitler, was well known for, among other things, his insistence that big business did not make a pivotal contribution to the rise of Hitlerism. GM, however, declined to release Turner's internal report or discuss the company's Nazi-era or New Deal-era history or archival holdings when contacted by this reporter. In February 2006, corporate spokeswoman Geri Lama twice refused to give this reporter the location of the company archive. In November of this year, Lama was again asked for an on-the-record response. She said she was referring the question to "staffers," but after more than a week, no reply had been received. GM has maintained a special combative niche in the annals of American corporate history, achieving a reputation for suppressing books, obstructing access to archival records and frustrating critics from Ralph Nader to Bradford Snell. GM attorneys even fought efforts by longtime company president and chairman Alfred P. Sloan himself to publish his own memoirs, although the autobiography was finally published in 1964 after a long court fight. In July 2005, Turner published the book General Motors and the Nazis: The Struggle for Control of Opel, Europe's Biggest Carmaker (Yale University Press). The book features 158 chapter text pages of carefully detailed and footnoted information, plus notes, an index and a short appendix. Although the book has been reviewed, BookScan, which tracks about 70 percent of retail book sales for the publishing industry, reported in late October that only 139 copies of the Turner book had been sold to the key outlets monitored by the service since the publication's release. In his book, Turner, relying on his work as GM's historian, disputed many earlier findings about GM's complicity with the Nazis, concluding that charges that GM had collaborated with the Nazis even after the United States and Germany were at war "have proved groundless." Turner rejects "the assumption that the American corporation did business in the Third Reich by choice," asserting, "Such was not the case." Turner also states that GM had no option but to return wartime profits to its stockholders, since "the German firm prospered handsomely from Hitler's promotion of the automobile and from the remarkable recovery of the German economy." However, Turner does state explicitly that "by the end of 1940 more than ten thousand employees at Opel's Russelsheim plant were engaged in producing parts for the Junkers bombers heavily used in raining death and destruction on London and other British cities during the air attacks of the Battle of Britain." Turner also condemns GM for taking the Opel wartime dividends, which included profits made off of slave labor. He writes, "But regardless of who [in the GM corporate structure] decided to claim that tainted money, its receipt rendered GM guilty, after the fact, of deriving profit from war production for the Third Reich made possible in part from the toil of unfree workers." Aware that questions would arise about his relationship with GM, Turner's book states in its preface: "This book was not commissioned by General Motors. It was written after the documentation project was completed and without any financial support from GM. Its contents were seen by no one at GM prior to publication. It is therefore an independent undertaking by the author, who bears sole responsibility for its contents." Turner did not respond to voice mail and e-mail messages seeking information about his sponsored GM history project, his subsequent book or other relevant topics. The GM Opel documents assembled for the company's probe and Turner's commissioned examination were digitized on CD-ROMs and donated to Yale's Sterling Memorial Library, where the collection is categorized as being "open to the public." In point of fact, the obscure collection can only be viewed on a computer terminal; print-outs or digital copies are not permitted without the written consent of GM attorneys. Sterling reference librarians, who are willing to make the collection available, complained to this reporter as recently as October that they do not know how to access the digitized GM materials because of a complicated and arcane database never before encountered by them. One Sterling reference librarian answered a question about the document by declaring, "I have spoken to two reference librarians. No one knows anything about it [the GM Opel Collection], no one is in charge of it. No one knows how to access it." Yale archivist Richard Szary, who supervised the accession of the collection, said that for the approximate half-decade that the documents have been on file, he knows of only "one or two" researchers other than this reporter who have had access to the papers. Szary, who was previously said to be the only Yale staffer who understood how to access the materials, facilitated this reporter's on-site access. He has since left Yale. By late November, however, in response to an inquiry by this reporter, a senior Sterling librarian said her staff would "figure out how to make it available" by reviewing technical details. Simon Reich, who compiled Ford's Hitler-era documents, bristled at the whole idea. "Ford decided to take a very public, open and transparent route," he stated. "Any serious researcher can go into the [Henry Ford] archive, see the documents in paper form, and have them copied. Compare and contrast this with the fact that GM conducted a very private study and the original hard-copy documentation upon which the study was made has never been made available, and today cannot be copied without the GM legal department's permission." Between the unpublished GM internal investigation, the restricted files at Yale and the little-known insights offered in Turner's book, the details of the company's involvement with the Hitler regime have remained below the radar. Nonetheless, GM's impact in both the United States and the Third Reich was monumental. On January 15, 1953, company president Charlie Wilson was nominated to be secretary of defense, a job that would ultimately see him usher in the era of the interstate highway system. At Wilson's confirmation hearings, Sen. Robert Hendrickson (R-NJ) pointedly challenged the GM chief, asking whether he had a conflict of interest, considering his 40,000 shares of company stock and years of loyalty to the controversial Detroit firm. Bluntly asked if he could make a decision in the country's interest that was contrary to GM's interest, Wilson shot back with his famous comment, "I cannot conceive of one because for years I thought what was good for our country was good for General Motors, and vice versa. The difference did not exist. Our company is too big." Indeed, what GM accomplished in both America and Nazi Germany could not have been bigger. Edwin Black is the author of the award-winning "IBM and the Holocaust" and the recently published "Internal Combustion: How Corporations and Governments Addicted the World to Oil and Derailed the Alternatives."