The author attempts (and succeeds!) in creating a history of the Third Reich that combines detailed narrative, analysis of trends, and moral judgment in a seamless whole. The author is not quite the prose stylist that William Shirer was, but makes up for this in the massive amount of detail he assembles and pieces together to tell the story of the incomprehensible.
Evans states in his introduction that he was inspired by several previous histories to attempt to blend their different perspectives while tapping into recent historical analysis and discoveries about the period. His description of the rise of the Third Reich goes far beyond Shirer's simplistic attribution of the rise of Hitler to the family dynamics inspired by Martin Luther, and succeeds very well in showing that Hitler's rise to power was anything but inevitable. Rather, Hitler achieved power as a result of disastrous mis-calculations of more powerful men who thought to use him as a tool -- and he was more than willing to encourage their fantasies. As Sebastian Haffner has said, Hitler possessed not the eye of an eagle, but rather than of a vulture, for siezing upon that which was about to destroy itself and exploiting it for his own ends.
I can only add that Henry Kissinger's doctoral disslertation pointed to a very similar phenomenon around the time of Napoleon, which Paul Krugman has extended to the Bush years: the people around Hitler did not stop him, because they could not believe that he rejected and intended to destroy the entire system of power distribution that they embodied. The powerful always have trouble believing that a revolutionary outsider truly means to destroy the old way of life, and continually look for a way to buy him off, only lending him power in the process.
A crucial insight, too little remarked upon, and Evans gives a vivid and at times moving account of the tragedy of this process.