This is a helpful concept I was introduced to for improving how to delegate tasks and responsibilities. These are levels of authority you give to others when delegating.
The Virgin Way by Richard Branson Summary
Richard has some great thoughts about passion, note-taking, listening, leadership, hiring, and delegating. I especially recommend reading if you are looking for advice on these topics.
Spiritual Leadership Book Summary
Spiritual Leadership one of the best books I have read. It is powerful, deep, and dense with substance. It contains a multitude of applications for leadership and management. My favorite chapters are 12: The Leader and Time and 13: The Leader and Reading. Chapter 13 contains practical applications on what to read, how to read, and how to get more out of what you read.