I'm currently reading Stephen Covey's latest - "The 8th Habit"; following of course his best selling "The Seven Habits of Highly Effective People".
On the subject of management and leadership he summarizes the themes and concepts of many other authors. (Give him credit for some humility.) What sticks with me are the stated principles of: 1. Set the direction, 2. set an example, 3. define the values, 4. provide the systems; then let people manage themselves.
My own summary of management has always been simply to communicate the objectives and then remove the obstacles to achieving them. The guiding principles may be simple, it doesn't mean they are easy to follow.