I read some of Friedman's book. I had no idea what it was going to be about. I was looking for anything I could find on Kahane at my local library.
It is true, most of the book puts him in a very bad light. I sincerely hope that most of the book's claims are false.
It does have some very good pictures of Rav Kahane, and even a cool picture of Chaim from the mid 1980's! "Crazy Jews"