The book was written with diligence, commitment, and attention to detail. Writing it took some serious research, lots of work, and, first of all, some serious love and fascination for Tchaikovsky. I understand that Klaus himself rewrote the German version into English. Reading the book took absolutely forever and it seriously tired me out. Too much misery, depression, sadness, loneliness, alienation, morbid fascination with death, and too many unfulfilled desires. Was Klaus trying to write his own "Death in Venice"?
But still, it was interesting to revisit the late 19th century Europe, read about Mahler, Grieg, Brahms, and so many others, although unfortunately they didn't really have too many interesting things to say. Klaus had a definitely very negative view on performers (Adele Aus de Ohe, Siloti, Sapelnikov etc), they are all shown as egocentric and ridiculous in their single minded pursuit of success and money. I found it a little disturbing.