It's well written - and I think back to Splinter of the Minds eye, which was kind of hard to put down, but here the writing style is not really the Sci fi genre from that period. It's much more grown up. The result is far more hard than some people will like.
There's a message here - very clearly... it doesn't matter what you've got, or what even people think about you too much. Don't get heated about the fact that you are not given the rank of master. Or even if you don't get the girl of your dreams. What matters is WHAT YOU ARE - your character.
To be honest, I think that the backstory in ALL three movies, I, II, and III is a very hard act indeed. It is debatable (and should be anyway, as all good art creates debate)that it all works seamlessly... We're caught in a story where we know the end - that's one thing - but in episode I, it is shocking to see the little boy, because of his real history, which we kind in advance, and his real circumstances.... EVERYONE wants him to win a bit, for him to be free, for his mom to be free. It puts the viewer into quite a state, because by the time we get to III we are certainly on his side. What happens in III, is, therefore likely to be extraordinary. I can assure you that it is.
I have to be honest, the transformation does not quite pay off. But it's very effective when it does even partly convince. It is very hard not to get very involved when you see the webs of darkness slowly creep over the stage, as it were, and harder not to want to jump into the book and warn Anakin - as if that were possible.
The novel may well scare you. The genius is making what can be made believable touch you personally. As Lucas said, the Sith is in all of us. To quote Johhny Cash, "if not for love, I could be one of these", and in fact, the possibility that love itself without the virtues of temperance creates Vader is really the real terror that criss-crosses the book.
But finally, the book closes in perhaps the worst way imaginable. To BE Vader. To live in pain forever, and never be able to stop the machine that encases you from working, and to have lost the only person that you loved, who was the love of your life, because.... Oh my. I hope we are all spared that.
How wonderful it is that even after all this, we do know at the end that mercy and forgiveness extends to Darth Vader. That's certainly good news - more than that, it's wonderful, amazing, unbelievable, but that ladies and gentlemen, is the miracle that we call grace...
Which, incidently, isn't Science Fiction at all.
Don't miss it.