The writer himself had the honesty to say, in the preface, that the Federer family did not think it was the right time to write a biography about a man still building his legend and not retired from the sport.
That said, this book was a big, I mean HUGE, dissapointment. It's nothing more than a fan declaration of love for Federer, with almost no insight into the man himself and with a lot notes cited from interviews in other magazines. A typical below-par unauthorized biography. It could almost have been written by checking Federer's results at ATP official site.
I unfortunately lost my time reading this one.