I see that another reviewer has already said most of what I was going to, so I will be somewhat briefer than I originally planned.
In terms of promising opportunities, this book has few competitors in modern-history journalism. As a young student, Frank Brandenburg managed to become friends with many of the most iconic survivors of the Third Reich: SS General Karl Wolff, Major General Otto Remer, ace pilot Ulrich Rudel, Hitler's personal secretaries, etc. He did it, he claims, out of personal curiosity, having watched the TV series "Holocaust" and wanting to learn more of Germany's past from those who had actually lived it.
The old Nazis, probably glad to have someone -- Anyone -- who wanted to hear their stories without heaping abuse or moral condemnation on them, opened up to him and trusted him with their own private views on the history of the Third Reich. (Perhaps unsurprisingly, they all inclined strongly toward what is nowadays called "Holocaust denial" and considered most stories of German atrocities to be mere Allied propaganda.) If we are to believe him, he had an all but unparalleled degree of access to their circles. His book could thus have been the first (and last) ground-breaking study to let these people speak out in their own words -- Not necessarily to be believed in every particular, but to be heard and recorded for posterity.
Ultimately, however, it all fizzles. For rather than producing the "oral history" he thus had a nigh-unique opportunity to compile, Brandenburg went off on a conspiracy trail, obsessing over the idea that Martin Bormann remains alive and is heading a secret underground of neo-Nazis threatening German democracy. His story, as treated by prolific writer of Nazi-themed spy fiction, Ib Melchior, is presented in the breathless manner of an old comic book or modern TV series, with dramatic cliffhangers and ominous forebodings. From the sinisterly portrayed old Nazis, we hear very little of historical substance (and even less not already published in their assorted interviews, memoirs, etc.) -- Mostly they simply seem to provide background to the "X-Files"-like investigation of the grand conspiracy. Elementary factual errors also abound in the narration.
The reader is thus left with only tantalizing hints of what this book could have been, had young Brandenburg chosen a more historical emphasis. There are fascinating little portraits of such men as Karl Wolff or Hans Baur, as they appeared to him in the early 1980s, and once or twice they are allowed to say something of historical interest. But on the whole, actual history is ignored in favor of what seems a semi-fictional, in any case much exaggerated, present-day thriller. The tremendous potential of Brandenburg's connections is left unrealized, and his and Melchior's book contains relatively little that will be of interest to the researcher.