The Pursuit of God, by A.W. Tozer. Nook.
This little book is rightly considered a modern classic. Tozer's practical teaching on the work of Holy Spirit in the believer's life is insightful and penetrating. Although not an academic work, Tozer's knowledge of the Bible and of human nature are among the strengths he brings to this work.
Tozer refers to himself as a Fundamentalist in the book, but the word did not have the hard cultural edge that it does today. As a matter of fact, he calls his fellow Fundamentalists and Evangelicals out on their propensity to separate from the world. Tozer's view of the life of faith calls for an active involvement in the things of the world.
There have been many wonderful books on Christian living published over the centuries, and certainly many in the 20th. But this one deserves its place alongside the classics.