I have read this book thoroughly and have reasons to argue that despite its fiction- like narrative and occasional lapse into author's sentimental judgement coupled with horrific description, this book can be a tool for soul-searching for us Muslims especially to understand what ails us.
It's a fact that split emerged or power struggle ensued since the moment the Prophet (pbuh) breathed his last. That power struggle caused not only the split but also our gradual distance from the lofty ideals of equality and equity of the Prophet (pbuh) and those of the rightly guided Caliphs.
The author has quoted Tabri an authentic muslims historian. I recommend this book to be read by a vast majority of muslims over the world.