They Smell Like Sheep by Dr. Lynn Anderson is one of the best books I've read in a long, long time. I think it's a must read for Pastors, Elders, Deacons, any Leaders in the church.
He focuses on the simplicity of what it means to mentor someone, what it means to pastor someone, and ends with the authority that a Pastor has (or doesn't have) amongst the sheep.
It's an easy read and very interesting. I highly recommend it!