This book shows how the cinema paralleled and sometimes helped form the German psyche. Yet it is more than just a documentary. This brings you from the beginning of the industry to show what Hitler inherited. However the information caries far beyond the political dimension.
I use it more for information on the film industry as a whole for that time and the basis of what we inherited today. It is interesting that from the beginning people complained that the film was to long and inclusive or too short and excluded characters form history or books.
Two good parallel and overlapping timeline books for the era are "Caligari's Children : The Film As Tale of Terror" ISBN: 030680347X Which is a different view on the same subject and "The UFA Story : A History of Germany's Greatest Film Company, 1918-1945 (Weimar and Now: German Cultural Criticism, 23)" ISBN: 0520220692
They tried to capture the feel of the time and of the German actors attitude toward film, in the movie "Shadow of the Vampire"