Terrible, dreadful, awful. Stay as far from it as you can. It is yet another example of the froth and the spume that is continually churned out by some evangelical publishing houses. It provides for the reader what pop-psychology books supply--the intellectual and spiritual equivalent of a sugar-rush followed by the inevitable low when one comes to realize that it isn't possible to act upon it in the way the author has indicated.
The chief problem with the book is that Warren gives very little time to the real purpose of a purpose-driven life--the praise, worship, adoration, and profound love of God particularly through His Son Jesus Christ by the power of the Holy Spirit. Grace gets very little play in The Purpose-Driven Life.
In our last discussion of this book, Warren made the point that we are all called to "mission work." My reponse was, "So every member of the body of Christ is a foot?" This is just one example among many of the kind of facile gloss with which Warren approaches the spiritual life. What is most disturbing is that the audience for something like this is committed Christians, people who ought to know better and ought to be able to see through this surface. I don't say that the book will led them astray, but I do say that it strands them on an island of self-motivation largely apart from the bounty of Grace.
One gets the impression from the book that if you took it in your mind to do so you could become an evanglist like Billy Graham. Patent nonsense. Surely, if you are called to that by God and supported continually by Grace, it may happen. But the actuality is that very few of us are called to serve our brothers and sisters in that way.
Do not be taken in by this book. It will lead only to disappointment and disillusionment as the glow from forcing yourself though three hundred pages of execrable prose and even more execrable reasoning in a mere forty days wears off. Do yourself a favor and spend the forty days reading Dickens or Austen. It will do every bit as much for your spiritual life, and leave you with a legacy of great Art as well. (Austen never disappoints, and Dickens only rarely. Speaking of Dickens, another observation regarding the book: If one were to act upon Warren's words literally, we would become a nation of Mrs. Jellybys with children running wild in the streets while we meticulously tended to the mission in Africa.) No, we've been warned many times against this by better works.
Do not be drawn in by the enthusiasm of adherents. Read instead The Imitation of Christ, Introduction to the Devout Life, Practice of the Presence of God, or Story of a Soul. These are works that inspire devotion, love of God, and service with roots solidly in Grace. These are proven works--proven by the sanctity of the people who wrote them and proven by the grace of God which has beeen showered down through the ages on those who read them. Become a person with a real purpose by reading the Bible and learning to love, worship, praise, and adore our loving Father and His whole creation. But for heaven's sake, leave Warren on the remainder tables where he belongs.