Peter Drucker, whose clear thinking and engaging analysis made him the epitome of the management guru, has died at the age of 95. Never an economist, nor even a businessman, Drucker was a journalist. He just knew the right questions to ask. His questions made us better people, as well as more effective mangers. His creed of value and service first, profits later, gives business a human purpose like few others. And his questions should be asked every day by us all: What is our business? Who is the customer? What does the customer value? Bruce Marcus puts Drucker into context for professional services firms in “The Death of a Giant.”