Excerpted from , by Justin Menkes

To master the process of soliciting the best performance from their people, leaders must first understand one essential truth about human psychology: that every human being is capable of both mediocrity and greatness. We assume that there is one person in each body, but each of us is more like a committee whose members have been thrown together to do a job. Consider two of the most widely revered leaders in business—Peter Drucker and Jack Welch.