The first part of the book, until ca. 1970, is excellent. More detail and various perspectives on Warhol's artistic development you could not reasonably demand. I'm biased towards the period between about 1962 and 1968, more interested in hearing about the early Factory than anything else.
As many other people have said, the first few chapters are fascinating for the psychological 'case' that Bockris builds about the mature Warhol based on the childhood he describes in these introductory chapters. He pursues that case throughout most of the book, essentially arguing that Andy's adult personality was adapted from that of his mother, Julia, as he applied her practical-minded work ethic and desire to please as well as her less flattering traits-- controlling people who depended on her through manipulating their self-confidence, for example. The picture Bockris paints of the Factory's most unhinged period around 1965-67, highlighted in the film The Chelsea Girls, offers both of the prevailing perspectives on the social scenario at the Factory during that time. The pessimistic perspective is that Andy manipulated the emotions of vulnerable young people who looked up to him, and cut them off once he started losing on the deal. The optimistic perspective essentially says that Warhol's Factory had a magnetic pull for unstable but frequently brilliant young drama queens (of all genders), and Andy gave them the daily structure they craved as well as a purpose in life, in the form of conceptual art and becoming a star in one's own mind. Andy had the personal stability they relied upon, but they had the conceptual material and uncompromising intensity of youth, which he desperately needed to stoke the flames of his art. I'm more inclined to take the latter point of view, but wouldn't I? Haha..
The second part of the story, which I count as 1970 through Warhol's death, is for me too ugly to love but too boring to take a prurient interest in. Andy Warhol as New York disco "tastemaker" figurehead, lead around to the 'hip' clubs and restaurants by his unctuous handlers like Bob Colacello, whose bio. of Warhol I'm glad I didn't buy before reading this book. I had to take off one whole star from my rating for this part of the book, which is several hundred pages actually. Maybe I was so satisfied with the parts of the Warhol story that interested me, I felt no need to pay the last chapters any more than skimming attention. Maybe my tolerance for watching the fatal flaw unfold to its conclusion is weak. I was never big on Greek tragedies.
PS: One last comment: the few moments in Warhol's story, as Bockris tells it, that I found very bitter pills to swallow, were the times when Andy gave up on his close collaborators and even friends (if the man truly had any friends) once they failed to be what he required of them. The two huge instances of this behavior are his complete indifference to Candy Darling's death from leukemia in 1974, and his disappointment in Ondine's personality once he gave up taking amphetamine. I can understand that death and dying were traumatic to Warhol, too traumatic to endure first-hand perhaps. But he seems literally to have forgotten these people, almost overnight. Well, in Ondine's case he got him a job at Carnegie Tech were he went to art school, it seems. That slightly assuages my anger at reading about his treatment of these friends. He seemed much more interested in taking care of people's material needs, however, than showing any real interest in their lives after he had apparently lost the ability to be interested in them, however. The preoccupied rich daddy. Maybe Edie Sedgwick was attracted to Andy for a reason.