On balance an excellent movie. I won't bother to rehash the plot, which has been amply covered by previous posters, but will say that the production values, acting, and script are all top-notch. I found this adaptation of the 1964 Hans Hellmut Kirst novel to actually be superior to the book (how many movies can claim that?). I think screenwriter Paul Dehn tightened things up a bit, plot-wise, but for those who still insist that "The Night of the Generals" is over-long, I would point out that distilling any 300+ page book down into even a 146 minute screenplay is no easy matter. I'd prefer a longer movie to a butchered storyline any time. My main complaint against the novel is that I simply didn't care for the writing style of Kirst, which I found very turgid. Of course, I admit that writing style is a matter of taste, but I'm glad the movie didn't slavishly follow the book in tone.
The switch of General Tanz from Wehrmacht to Waffen SS was a bit jarring, but historically speaking, is not without precedent. I think the reason they use this device was simply to further highlight Tanz' descent into evil and madness -- having him join a notoriously evil organization (whether such a move was cinematically necessary is debatable, considering Tanz' obvious lunacy).
The tanks used appear to be fairly good recreations of the Tiger tank (though not exact), which is refreshing after seeing so many modern American tanks pressed into service as German types by Hollywood. The sets are uniformly good, from the Warsaw Ghetto to the garrison of Tanz' division in occupied France (actual French fortifications of the period were used for the filming, just as they had actually been used by the occupying Germans during the war).
Unlike many posters, I found the subplot involving the Hitler assassination attempt in 1944 to be the high-point of the movie, lifting it from a mere murder investigation of prostitutes into the realm of one of the most interesting and important events of WWII. Had the plot succeeded, 10 months of bloody carnage on the battlefields and in the extermination camps would have been saved. The recreation of the bomb-plot is not completely accurate, but reasonably enough so. (Of course, it's best not to look too closely at the rather prominent lump on the side of Von Stauffenburg -- where actor Gerald Buhr's arm was hidden under his tunic!) But the including of the bomb-plot not only serves to tie together the storyline, but provides real excitement (even though we know it's going to fail).
Kudos to Omar Sharif for his portrayal of Major (later Lt. Colonel) Grau, though I agree that maybe he could have gotten alittle more screen-time (in favor of the over-abundance of scenes with nerdy Tom Courtney!). The Grau character itself is, however, alittle too "good to be true". While obviously seeing the point about contrasting murders large and small, I have to wonder just what really drives Grau in his pursuit of "pure justice"?
Grau simply comes off a bit too "holier-than-thou" for as high a ranking officer as a Lt. Colonel of Intelligence in the German Army. A truly principled man would not be serving such a despotic state in which justice had visibly been denied so many in Germany (starting in 1933)...to say nothing of murdering & enslaving neighboring peoples. If Grau were so high-minded, then how could he serve such a master? I would of found him more believable had he simply had some other motivation for pursuing the killer, such as wanting to further his career by landing a "big fish", or perhaps some smoldering resentment against "Army brass". The idea that Grau was so lily-pure that he yearned only that justice be served might be believed in some other army, but not Nazi Germany's! (Besides, even had he nailed Tanz for the murders, does anyone really believe that "Hitler's favorite" wouldn't have been quietly and quickly released? After all, this is Nazi Germany -- hardly a paragon of virtue!) Ultimately, in a strange turnabout, General Kahlenberg (Donald Pleasence) is doing more to fight evil by trying to rid Germany of Hitler than Lt. Col. Grau with his insignificant murder investigation.
As for all the comments about non-German actors portraying Germans and speaking English...I would think that everyone would be used to that by now, after 80 years of sound motion pictures! That the mostly-British cast doesn't attempt "authentic" (???) German accents is good. After-all, to be really "authentic", the actors would be SPEAKING German -- not English with faked German accents! And frankly, I find reading subtitles tedious -- so I don't mind "Germans" (or anyone else in movies) speaking English.
Finally, I agree that the switchbacks between WWII and 1960's can be alittle jarring, but it does serve the plot line, and is an interesting narrative style of both book and movie. I would also agree that the end of the picture, which takes place in the 1960's, is somewhat anti-climatic, especially after the shocking scene of Grau's murder. But it IS necessary to tie up the storyline which would otherwise be left dangling. Obviously Inspector Morand couldn't do anything back in 1944 in Nazi-occupied France, so to have him solve all the murders (including Grau's) in "modern" times is a good final touch (though one may wonder why he waited so long to do it -- after all, the war had been over for 20 years...perhaps he had his suspicions of Tanz all along, but no proof, until the Hamburg murder.) At any rate, "The Night of the Generals" is good enough to qualify as MUST SEE cinema!