1) Positive
This is the biography of Yves Saint-Laurent, the most comprehensive to date.
Book full of information, also in the annexes. The chronological place at the end of the book, year by year, regarding YSL and Pierre Bergé, is interesting.
2) Bad points
A disjointed narrative style. A lack of structure of the narrative. In the text, we get lost in the chronology of events.
Flat style, lack of perspective: the author strikes us a hodgepodge of details on the zeitgeist, is lost in the details without highlighting things and important characters (many of them are cited to hurry and many of them are not mentioned) that revolve around YSL (except Pierre Bergé). In sum, details and important things (not all) are placed on the same plane.
The author quotes at the end of the book, the book competitor Alicia Drake (long passage of a page) to criticize him. Approach not very friendly, especially since it is much better written.
3) Suggestions
Read also, in addition, the work of Alicia Drake ("Beautiful People: Saint-Laurent, Lagerfeld: splendours and miseries of fashion"), which is exciting and remarkable writing.