I would rate this book as 4.5. I have the hardback editions and this book is a near classic on revival as it gets.
Some of the early chapters are hard to digest, so its not an introduction to revival, but some of the later chapters are very easy to understand and the bits on the fullness of time are very good. The publisher or author acknowledged these short-comings and have removed them and published 'this' shortened version under another title.
All in all, this is a very good book and comes highly recommend by myself.