Prayer: Experiencing Awe and Intimacy with God by Timothy J. Keller
My rating: 5 of 5 stars
Despite his critics, I found this overview of prayer exceedingly helpful. He bases his explanation of prayer primarily on the works of Martin Luther, John Calvin, John Owen, and secondarily on a few patristic and contemporary sources. The most beneficial part of this book, for me, is that it has given me impetus and resources to reform my method of prayer in a way that I believe will be more God-glorifying.