I seem to be at odds with almost everyone here. I have long been a fan of Hockney's art, and, oddly, after reading this book I like him less. Maybe that's not a criticism of the book, since a biography, even a fictionalized one, is meant to portray the subject character realistically. But the Hockney in this book is devoid of humor, self-indulgent, controlling, and borders on a sexual predator in his relationships with much younger men (though I have to admit the relationships seem to be consensual). He also seems to be a man with one emotion at a time, which strains credibility.
I mention having been a fan, and realize that I was a fan of the art, and knew little about the man. Somehow the descriptions of the art in the book are faintly repellent to me. I have never thought of him as derivative, but critics certainly say that. And his later work sounds repetitious and I can't see myself liking it. But it is a problem of the book that it, by design, lacks illustrations. To me, descriptions of art without actual depictions is bound to fail, or at least it did here for me.
Maybe the book reads better in French, since the French comments are all very happy with it. It is, of course, hard to gauge a writer's style from a translation. However, to me this book read like its target in terms of reading ability were English-speakers in middle school. The book I just read before this was also a translation from French ("Exposed") and I found the prose lovely, so it is certainly possible for literature in translation to impress me.
It is always a downer for me to read a work of fiction in which I like few of the characters, and that is what happened here. The men are all gorgeous (the women are less glowingly depicted in terms of appearance), but seem to have similar personalities (and bodies, for that matter). I was also uncomfortable with Cusset making it clear that a number of Hockney's friends and lovers were Jewish. It's never discussed beyond stating the fact, which makes me wonder why this seemed important enough to include.
When I started reading this, I fully expected to like it and learn interesting things. Other readers clearly did, but I have to record here that I was disappointed. I expected more, but maybe that was inappropriate given how short the book is. Oh well.