I will hold my fire on this until I've read it.
We should be able to tell if it is biased or factual by the reviews and TV interviews of the author.
This book may be considered, in the future, the history book of the Clinton presidency. What other book is there by someone outside his administration, or his right-wing detractors?
If his flaws, deceits, failures, strengths and successes are honestly discussed and portrayed, then it will have merit.
If it's accurate, my guess would be that there WON'T be reviews and interviews. The MSM will ignore it. If it's a glowing book that excuses Clinton's lies and malfeasance, he will be all over the airwaves.