It is one of a kind. Kohler does an incredible job to explore the relationship between music and ideology through Hitler's fascination for Wagner's compositions. It was, in some sense, impossible for Hitler to become Hitler without his obsession for Wagner's plays and operas.
Total bunk. Selective, short, piecemeal quotations. Disingenuous end-notes (Köhler quotes his own work when the reader is expecting a contemporaneous report). Wild speculation given as fact. "Must have" "could have" "may have" "might have" on almost every page.
It's okay. The author makes some good point, but overall, he overstates his case. Falls under the structuralist viewpoint of National Socialist history.