The traditional view of Hitler and the Reich was that Hitler dominated all aspects of Nazi policy, and that the entire drive to world domination and genocide was driven by his ideological fanaticism, all of which was set out in frightening detail long before the seizure of power (1933) in Mein Kampf (1925), that turgid and rambling ideological autobiography.... This interpretation has been dubbed by modern scholars (with their usual love of trivializing labels) as the "intentionalist" or "monocratic" position - and is what most of us have been exposed to. But beginning with the work of Martin Broszat, Hans Mommsen, and others -- a new view gained popularity: Hitler was hardly a powerful dictator (they claim), but a weak center around which swirled a powerfully dynamic leadership fragmented into small power-cartels, like neo-feuldal lords...; that Nazi Germany was actually a "polycracy". Further, in nearly every area -- economy, administration, domestic matters, foreign policy, and in anti-Jewish legislation and, ultimately, even in the establishment of the "Final Solution" (Endlösung; so, e.g., the works of Christopher Browning) -- German policy (and the Nazi Leadership) simply stumbled forward with no set plan, improvising ad hoc solutions to problems that arose. Before 1942 Spring, e.g., all they wanted to do was "deport" the Jews -- and the rational organization of killing arose from local initiatives put in place by local lords in Poland who were simply swamped (poor guys...) by all the recent "deports" and who, ever efficient and ambitious (i.e., less ideological) devised the only possible solution to their problem. This is now the consensus view of the Holocaust. This general approach to the problem of Nazi Germany is called the "structuralist" position.
Kershaw -- Sir Ian -- who's two volume biography has earned him great honors (there is now a one-volume abridgment available (2008)) -- is (though usually quite sensible and never extreme; Mommsen was, by contrast) a 'Structuralist'. This book sets out the scholarly debate in various spheres, shows how the various positions were developed (and by whom), and then defends the structuralist position. Kershaw is steeped in the German literature and is authoritative.
This book is therefore very important, and of great utility to students of the topic -- even if one can barely endure his approach. A.J.P. Taylor, the great British historian (and reactionary) once said that there was nothing wrong with Hitler in foreign policy, except for the fact that he was a German. Niall Fergusson, who gets so much press these days, wrote his principal academic book (The Pity of War) blaming Britain (not Germany) for WWI. Kershaw is not so bad as these two. He even voted for Tony Blair, apparently.... Still, reading this book required some strength of character on my part.
Worse -- it is poorly written -- the proof- reading is flawed -- there are anacoloutha everywhere.... Often I had the feeling, while reading, that either I or Sir Ian was dyslexic.... and of course I assumed it must have been me... (till I would re-read the offending sentences....).
Bosworth's book on Italy (below) does not have these vices -- though Bosworth has a more mediocre mind than does Kershaw -- and it is his (Kershaw's) undoubted brilliance, ultimately, that makes this book informative and worth the read.
(The complementary volume on the Italian side is: