Tozer is a straight shooter!!
This book is excellent. If you are going to read this, I would also recommend reading the book "The Pursuit of God", also by Tozer, which is about the same length. It is a companion book to this one, covering much of the same truth, but from a different perspective.
This book is a call for the body of Christ to get back to being real and pure, to drop all of our "religion" and to re-find (or find for the first time) our relationship with God. How God's desire is to have intimacy with Him.
Tozer is an amazing writer, honest and blunt in his communication. One could easily get offended by his words, but this is just a call to the offended reader that they are wrapped up in religion and not in God!
Anyone interested in what God looks for from us in dispensing revival would do well to study the preachers who helped bring about the past revivals. We may not be looking for copycat revivals, but our heart attitudes and desires will likely be very similiar to those which brought about past revivals!