This book continues the story on from where the TV series of the 4400 left off. It generally does so in a consistent manner, but some of the characters (like Richard Tyler and Tom Baldwin) speak in ways that they wouldn't have in the series. This is a major problem and is the first indicator that the writer really didn't get immersed in the world that this book is born out of.
It starts very slowly and tries to make itself accessible to those who aren't familiar with the series, but doesn't do a great job. My main criticism of this book is that the descriptive potions are short and lacklustre, because of this the book never conjures up enough to really grip the reader. Towards the end the action gets interesting, but it doesn't make up for the monotony of the majority.
All in all, a decent book at the £3.99 Kindle price, but not worth the paperback RRP.