E. M. Bounds
Here is a saint with whom each of us should become familiar, that we might learn from his service to Jesus. He prayed 3-4 hours a day, and wrote extensively on the subject of Prayer. I've found that ANY biography of E. M. Bounds is worth reading!
A Brief E. M. Bounds Biography
Some of the Works of E. M. Bounds :
Power Through Prayer, E. M. Bounds
The Necessity of Prayer, E. M. Bounds