Dr Genichi Taguchi died last month. I met Dr Taguchi several times in the 1990's (http://bit.ly/QOfCn7) when he came to Ford to help us. From him, and Don Clausing from MIT (who died in 2010) I learned most of my engineering. Like many others who have made fundamental contributions to our understanding of the way the world works, he simply reversed the order of things we thought we were already doing in the right order. It used to be thought that a design should first be made to achieve a target, and then the variability should be reduced. This approach often resulted in tighter than necessary tolerances, and thus higher costs. Dr Taguchi reversed this sequence; first reduce the variability (by finding design factors that interact with noises factors - the variation), and then work out how to get the thing on target. It's a beautiful idea, still not widely taught to undergraduate engineers.