It is 30 years since Peter Drucker hailed knowledge worker productivity as the great management challenge of the 20th century. By the 1960s we knew plenty about how to organise factories and logistics systems. But as the great sage of management observed, we understood next to nothing about how to get the most from doctors, lawyers,designers or marketingexecutives.

The century ended with the challenge still unmet. As Tom Davenport points out in Thinking For A Living, even today we lack "measures, methods and rules of thumb" for managing know­ledge work.