Leonard A. Schlesinger, Charles F. Kiefer and Paul B. Brown: 'You may have wondered why so many things seem to be harder and take longer to accomplish than you would lie-and why both things seem to be increasing. We don't have the answer in every case, but there is an explanation that probably covers the majority of situations; the way we have been taught to solve problems was designed for a different world. To deal with uncertainly today, we need a different approach.'