Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A wonderful, deep approach to prayer

I actually bought this book in hardcover from a bookstore. I'm a student of prayer, and an avid practitioner. I think it's the lifeline of our relationship with God. I was introduced to Philip Yancey in hisDisappointment with God, and that's where I came to love his insights. I love his thoughtful and personal style of writing, not afraid to go deep, not afraid to ask penetrating questions. I rank this book as one of the top leaders in the Christian prayer category, right up there with Stormie Omartian'sThe Power of a Praying Life: Finding the Freedom, Wholeness, and True Success God Has for You, and Jim Otis'sSecrets of the Inner Chamber: How to Experience the Phenomenal Power of Private Prayer,Secrets of the Golden Bowls: How to Experience the Extraordinary Power of Cumulative Prayer, andSecrets of the Armory: How to Experience the Enemy-Defeating Power of Warfare Prayer, all great reads on personal prayer.