This is an excellent book showing an incredible amount of research. It's very well written, the literary style is readable and entertaining - not the least bit dry or academic. The scope of the book very broad, relating developments in the history of ballet to contemporary events and to the zeitgeist.
However, the author is American, and she seems to believe that the latter half of the 20th century was exclusively American. She seems to think that English ballet died with (was killed by) Kenneth MacMillan. Darcey Bussell (surely the greatest dancer of her generation) gets just one cursory mention, and there is no mention of the host of international super stars schooled and nurtured by the Royal Ballet - Carlos Acosta, Leanne Benjamin, Wayne McGregor, Jonathan Cope, Irek Mukhamedov, Deborah Bull, etc. etc. etc. And there is scant mention of any late 20th century ballet anywhere in the world outside of America.
I would certainly recommend this book to anyone with even a passing interest in ballet, but I would recommend supplementing it with this one:
The Royal Ballet: 75 Years