In 1979 I set out with a number of colleagues at MIT to understand why the best Japanese firms seemed to be so much better at making things. At the time, the favored theories were low factor costs ("they've got an undervalued currency and low wages"), Japan, Inc. ("they cheat"), and culture ("they work harder"). We thought otherwise. Indeed, we believed that there had been a fundamental shift in the philosophy and organisation of manufacture - a shift moving the world from the age of mass production into a new era. However, it was hard to be absolutely sure that we were right. Convincing others was even harder.