The joints are stiff, but the mind remains agile. Peter Drucker turns 95 on Friday and continues to talk more sense than anyone about the real work of management.

"Managers learn in business school that relationships are either up or down, but the most important relationships today are sideways," he says with an Austrian accent grown stronger with old age. "If there is one thing that most of the people I know in management have to learn it is how to handle relationships where there is no authority and no orders. Now, what else do you have?"